What Causes Hard Lump On Lower Vaginal Area?

hi i was taking a shower and found a round hard lump on my lower virginal area close to my rectum,.i try to sqeeze it but nothing.only slight pian only when i try to sqeeze it.what should i do?i am 46 ,5ft 31/2ins.i did an histerectomy in 2007,i am diabectic type 2,wt140lb.