Yes, the PLRA governs all lawsuits brought by either federal or state detainees, but not immigration detainees.

Document as much as you can. What you are describing is not uncommon. Denial of medical care is sadly part and parcel of getting caught up in the American "justice" system. If you have actual evidence of the denial of medical care you might try reaching out to some local organizations in your state to see if they would be willing to take on the case.

PM me if you have any specific questions and if I can I'll try to answer them. Remember, however, that I am not your attorney and have no intention of entering into an attorney-client relationship over the internet.