I currently live in the UK in London, I would like to relocate to the USA?

While a visitor's visa is easy (assuming NO trouble with the law), getting a work permit is almost impossible unless you have some skill that is in high demand. Usually your USA employer obtains the permit for you. A licensed doctor would certainly qualify. Sometimes a school or hospital district in an improvised area (forget about Manhattan) can get a work permit for a teacher or a nurse. The problem is that you are stuck with that employer. If you leave the employer without finding another one to sponsor you, your vista will be canceled (usually you'll have 90 days to leave on your own) and you could be deported as an illegal alien. Once that occurs you'll never be allowed back even as a visitor.