What Causes Vaginal Bleeding?

i had a total hysterectomy 22 yrs ago. i am now exeperiencing vaginal bleeding. took hcg drops for 6 wks beginning first week of february off 3 wks and back on for a week. not sure when bleeding started. think back in january. just a little pink w/peed. went to dr thought uti. but no. and had scan for stones. had been taking major doses of aleve for shoulder problem (prescribed by dr). will go several days and nothing. havent seen any for a week or two and last night back. thought i would check vagina and that is source of bleeding.