Moving from Japan back to the U.S. (St. Louis)

Hello I have a chronic illness and need to enroll in U.S. health insurance. My parents are not insured and I am single. I really have no clue how the system works in my own country.

I’ve heard that people who have lived abroad have used traveler’s insurance to cover a few months until they get proper insurance. If anyone could enlighten me regarding this process that would be helpful!

If I work for something like Starbucks to get health insurance, would that be a viable option? I don’t really have any particular skill set other than customer service and translation… I’m basically going back to the U.S. to take credits at a community college to prepare for graduate school, and then by next year hopefully I’ll be enrolled in graduate school. The school seems to have options for insurance, which is nice… but I’m worried about being uninsured until then.

I need to get an endoscopy once a year and a daily dose of Proton Pump Inhibitors … I’m assuming that compared to Japan the price in the U.S. is probably 5 times as much or something. To be safe, should I get an endoscopy again right before I go back to the U.S.? Also is it possible for my doctor now to prescribe like a year’s worth of medication so I don’t have to purchase it in the U.S.? XD Can I even bring that on the plane?