I have a rash from wearing pads on the upper thigh area and one on the lips of my vagina. I used some A&D ointment but I'm afraid if I get too much near my vagina ill get a infection... so I guess my real question is, can A&D ointment thrown off my Ph Balance?

You don't have to worry about A&D ointment, it is very gentle zinc oxide used for baby rashes, usually fortified with lanolin. Will not give you any problems.