Have you ever seen a chiro? I would be interested to hear what they say about your condition.
To be quite honest (and you might not want to hear this), I would focus on getting healthy first and foremost, not on working your legs. Think about this: You are only 21 years old and you have these issues, what's your body going to be like when you are 30, 40 or 50? I'm more interested in your long-term well being than massive legs.
I'm actually going to meet a chiro here in town on Thursday, if I like him, I'll let you know and maybe you can get with him as well. In the meantime, I would really work on getting loosened up; check out my "Hardcore Stretching" and EC and I's "Feel Better for 10 Bucks" articles to get yourself started.