What Causes Non Painful Swelling On The Mons Pubis?

I am a 44 year old woman in relatively good health and just noticed a non-painful swelling of about 1.5 inches long by .75 inches wide on my mons pubis, about an inch in from the groin area. When massaged the swelling goes away almost completely, and then within minutes returns. There are no changes in color to the surface/skin. About 5 days ago I did some heavy lifting, and about 3 days a go I took Frova prescription medication for migraines. Any thoughts?