Me and boyfriend where having intercourse and it burn his penis and me as well I got tested for std's and HIV and iam negitive for all I recently had a CT scan and dr shot me up with some kind of medicine is that the cause

Hormone. If you lack estrogen , the vaginal mucosa may get too dry and causing irritation to both of you after intercourse. Do you still have regular periods?
First . First of all in order for me to try and help you i will need to know what medication you were given. If you don't know then i suggest you call the doctor and find out exactly what medication you were given and why. Please re-submit question with answers. Thank you.