I think i have bursitis. in the buttocks i can't sit without pain . it has been over a week. what is the best treatment?

Could be many things: There is a condition called ischial bursitis, that could improve with anti-inflammatory meds like ibuprofen. However, a number of conditions can cause severe buttock pain, including an abscess near the rectum, called a perirectal abscess, and a blood clot in a hemorrhoid. You should probably see a physician and be examined.

See below: Warm compresses/soaks, physical therapy, but the quickest relief comes from a physician injecting the site.