You can't move here without a visa -- unless you're already a citizen (but I don't see that in your previous posts). If you come over without a visa, you'll just be a tourist, which means you can stay here for six months max and you it'll be illegal for you to seek work.
It says in one of your other posts that you'll be living with your boyfriend. If you guys are engaged, you could come over on a fiancee' visa (plus you'll need a "marriage" visa...can't remember what they're called...something like a certificate of approval). The info for that is on the britainusa.com website.
You could come over as a student, but be prepared to pay substantial international fees.
Are you a recent college graduate? You could look into the BUNAC program, which would allow you to live and work here for 6 months. The only drawback with that is that it's difficult to find work other than waiting tables, etc., because you'll be here such a short time.
Once you're here on an appropriate visa, you will be entitled to treatment by the NHS.
