I have a lump on inside vaginal wall father in the back i can't see it but feel it with my fingers don't hurt and its golf ball size what might it be?

Vaginal mass.: In all likelihoid it is a bartholin's cyst. However, it could be a mass due to infection or tumor or trauma. Other causes include pelvic laxity with an associated rectocoele or cystocoele. Please schedule an examination.

Find another lump: A woman who reaches deep into her vagina and finds a golf ball sized lump must look for another lump. If she only finds one lump, it's probably her cervix! if she finds 2 lumps, one is the cervix, and the other one is for her doctor to look at.