Jason, As a practicing foot & ankle surgeon, I deal with flat feet on a daily basis. You likely have some decreased strength in your Posterior Tibial Tendon (inner leg/ankle tendon). You would probably do well with a pair of good rigid over the counter orthotics or possibly a pair of custom functional orthotics to help control your hindfoot/ankle and midfoot motion. I usually recommed Powerstep Orthotics or Superfeet "Green" as a good go to over the counter option which can be slipped in your golf shoes and increase your support and stability. If this isn't helping then consult a local podiatrist or foot/ankle surgeon for discussion of your foot pain and problems.

Jason, That is a very interesting story. Its definitely not something you see or hear about everyday. Let me start by saying I am a physical therapist dealing exclusively with outpatient orthopedics and some sports PT so this won't be complete BS. I prefer educated BS. Its difficult to fully understand the problem without seeing you in person but we'll give it a shot. Flat feet can be a really big problem and not just for the feet. The arch of your foot helps with energy absorption with walking, running, ect... If you lose your ability to absorb energy in your feet, it moves up the chain to the knees, hips, and low back and can lead to more serious issues. For example, my wife's uncle just had a total knee replacement due to arch collapsing issues. Now, your situation is probably not that grave, but don't ignore your feet is my point. The foot is extremely complex but I'll try to simplify here because I'm already off topic. There are 2 components to your arch, the bones and the muscles. If the bones are the issue, then you are structurally flat and would need arch supports to help. If the muscles are the issue, then you are functionally flat and this could be corrected by strengthening your intrinsic foot muscles. To check, look at your foot while sitting, with no weight on it. If its flat then, sorry, blame mom and dad because you got some bad genes but arch supports should help correct the problem easily as long as the arch is supple. If you have a good arch in non-wieghtbearing then your bones are good, but if your arch suddenly collapses in standing then the problem is the muscles. I'm sure youtube has great videos for intrinsic foot strengthening if this is the case and will help quite a bit but you have to work on it. You won't get strong muscles overnight, it takes dedication. If you're still awake through all that I'm getting to the balance portion of my rant. Sorry for the detour. Balance is controlled by 3 systems in your body: vision, vestibular (inner ear), and proprioception/somatosensation (or the feedback your body gets from the bottoms or the feet and joints). Since the only thing that is changing in the scenario you described is your footwear, or lack thereof, I would say somatosensation is the winner. It appears that in essence your golf shoes are hindering your body's ability to appropriately "feel" the ground below you and feel how your body is reacting to it. Think of standing on one foot on the ground, then stand on a couch cushion instead. Its a lot harder on the couch cushion because your feet don't know what the heck is going on. You've removed one component of balance and you are left relying purely on vision and inner ear. You can try this with the other system if you'd like. On firm ground try balancing with your eyes closed to remove the visual system. Try spinning around in circles then balancing to remove your vestibular system. In each case it becomes extremely more difficult to balance with only 2/3 systems functioning. I don't recommend trying all 3 scenarios at once, but if you're feeling good..... Now I'm no shoe expert so I'm going to speak in general terms here. Sorry I cannot advocate certain brands like you were likely hoping for. It seems that your shoes could be too rigid in the sole and too "cushiony" inside, or all around too soft. This would in essence create a platform off the ground with the rigid sole and then you are left trying to balance on the cushion. You are now living in the scenario where you are balancing on the couch cushion. When your shoes are off, you are balancing on the firm ground and receiving good feedback from your feet about what is going on below you, thus your balancing abilities are much improved. I'd rather not play golf standing on a couch cushion. You'll probably have to go to the local golf retailer and try on different shoes and testing your balance standing on one foot in different pairs. You'll look like a goober, but I've seen people do some pretty crazy stuff to lower their scores. You'll likely need a more firm shoe with a good arch support built in but try some different kinds. Sorry for the long rambling answer but that's what I do, I'm told. Good luck in your shoe search and if all else fails just grab a pair of those crazy toe shoes. It was all the craze a couple years ago with runners because it simulated barefoot running. I don't recommend running in them unless you have a gait that can handle it but playing golf in them shouldn't hurt anything. You're technically wearing shoes but it won't feel like it. Again, you'll look like a goober but if you beat your buddies then they can't really say much. Hope this helps some, Greg