Sorry I don't have any familiarity with what you're describing, but I do feel for you. Knee and leg problems have plagued me my entire life--all injury related, though--and I know they suck verily. I've recently incorporated a swiss ball into my at-home exercise routine (to get moving in the morning, essentially) and have found that it's nice and fairly non-taxing on my knees--I picked up a video called Zone, The Big Ball Workout for about six bucks at a used bookstore and the ball at Wal-Mart for about $13. The workout is based on Pilates principles, so you can probably imagine the types of movements it entails.

Like you, I somehow got the "put up, or shut up" mentality at a fairly young age. It was so ingrained in me that I once literally shattered some bones just below the ankle in my left foot and didn't even know it until almost eight years later. The bone fragments had fused together and I started having a lot of pain in the area. When I went to a doctor during my senior year of high school to find out what was going on, he started talking about how the bones had healed from the break. I, of course, told him that I had never broken a bone in my entire life...then he showed me the x-rays. The bone fragments had fused together, and there were still a few bone chips in the tissue surrounding it, and the combination was causing my pain. He wanted to perform surgery to remove the chips and shave down the lump the fused area had formed...and he wanted the surgery to coincide with some reconstructive surgery on my knees. This would have left me in a wheelchair for the entirety of my freshman year in college. I refused. So, here I sit with bad knees and an f'ed-up foot. (No, I'm not in the least bit stubborn. Why do you ask?)

Anyway, that's enough rambling for me. Do see a doctor, though. Legs are too important to not take care of...one day I'll take my own advice in that regard.