Is there a test to see if I have MRSA or a staph infection

Yes. A culture can identify the bacteria that is causing your infection. Staph and strep are common bacteria found with skin infections. After the lab identifies the bacteria that is causing your infection, testing is done to see which antibiotics would work best for your specific infection. Mrsa is a type of staph that is resistant to the drug methicillin, but other antibiotics are effective.
Yes. If a boil or abscess is present a specimen of the drainage or pus can be sent to the lab and a culture of the organisms is made. If staph aureus is grown on the culture then next it is grown on a culture with methicillin to see if the methicillin will inhibit growth of the staph. If growth not inhibited the staph aureus is methicillin .Resistant.