I agree that you should see your gyno for this issue. There are too many possibilities.
First, did you check to see if you have any type of growth in that area? And large cystic acne, abscess, tumor, or the like? I had a MRSA infection on my vulva that caused an abscess the size of a golf ball. It was the most painful thing I've ever experienced, causing throbbing through the whole region.
Second, do you see a chiropractor? It could easily be a pinched nerve that goes to that region. Chiropractors are nerve doctors, not bone doctors, and they specialize in freeing up nerves that go to places where you have pain.
Third, do you have bladder issues? Do you have a hard time "holding it in?" Feel like you might leak? Well, these can all be signs of major irritation. I have to add mineral powder to all my liquids, the same minerals in natural sparkling mineral water. I also have to avoid all acidic drinks, like coffee or juice, or sugar based drinks. This has entirely cleared up the irritation issues, relaxing my pelvic muscles and providing relief. You might want to try. I get my mineral powder through my naturopath, but you could try drinking strictly mineral water for a week to see if it helps. Non-carbonated is best. Mineral waters usually don't have enough minerals in them, but it is a starting point.