I get pink discharge for past week after rougher intercourse. have had ultrasound,pap etc for same issue and came back normal. what else could it be?

Mild inflammation: A mild inflammatory process probably due to the mechanical trauma to the soft/delicate genital tissues (of your vagina or cervix), during "rougher sexual intercourse" is the most likely explanation for your symptoms. A reaction to "foreign material" or to seminal fluids, if your sex partner was a man, is less likely.The discharge will probably disappear spontaneously if you have less rough sex.