Get the ultrasound (even little things like ultrasounds aren't free in the US??
)
I'm not thinking pulled muscle or hernia ... I'm thinking appendix, gall bladder, liver, bowel ... things like that. And yes, I happen to know from experience that a person can experience appendix pain can last for a year or more. It's called chronic appendicitis. But it needs an ultrasound, and if they can't see anything with that, then you need to go for a laperoscopy. You can also have gall bladder attacks for a long time ... they usually come and go depending on what you eat.
You're a college student ... didn't you get health insurance through your college when you paid your tuition? I'm a student too, and I'm covered for a whole pile of things all for the $125 insurance fee.