What would a dull ache that comes and goes just inside vagina in same spot right side be?

Levator Myalgia: It's not uncommon for some women to suffer from a condition called levator myalgia where the muscles that make up the pelvic floor begin to spasm and need to be relaxed and retrained via physical therapy or a vaginal muscle relaxant. Ask your gynecologist for a focused vaginal examination for pain and a referral to a pelvic floor physical therapist.