I should've rephrased my question, because I already know my bike doesn't fit me as well as it should, and that's probably a big reason it's causing me so much pain on longer rides. The main thing I was trying to find out is what might be medically wrong with me; shin splints, cowardness, etc.
I can't afford to go to a doctor since I have no insurance.
I'm 5'9", and my bike has a 22" frame, so I think it's probably too big for me anyway, but most of the time it doesn't bother me at all. Tours are the only time it messes me up really, and I figure a big part of that is simply because of the fact that I'm going from 25 mile rides unloaded, to 65-100 miles a day with a bunch of crap strapped to me and my bike. My butt, feet, knees, and ankles always hurt the first three or four days of any tour, but then it usually subsides and I can ride the rest of the time in relative comfort. This is the only time where I hurt this bad though, and I've still got some swelling and am hobbling around like a hunchback in a bell tower, but it's not as severe as it was yesterday, so there's hope yet that I won't be doing my next tour in an electric mobility chair.
I'm staying off my bike and feet as much as possible for a few more days at least (I'll starve if I don't get back to work though), but if I'm still this messed up a week from now, I'll go ahead and sell a kidney or some sperm or something so I can go to a doctor.
Hopefully, this summer I'll have the money to get a nice touring bike that fits me, but I'm stuck with what I got till then. Money aside, I'm not getting rid of this one till I get 20k miles on it anyway(I'm still about 3.5k miles away), even if it means I'm sterile, impotent, and crippled by the time I achieve that goal. I've got too much time, money and pain invested in it to quit now, and like I already said, most of the time the bike fitment doesn't bother me at all.