Do you have sores? Blisters?
How long has the pain been coming and going? Why didn't your doctor do the herpes blood test? You can get a type specific IgG blood test for herpes, but it can take up to 4 months to show positive.
It doesn't sound like herpes, and straining your pelvic floor sounds plausible, but since you're obviously worried, ask for the blood test to put your mind at ease.
I don't know what your possible exposures are, so I can't tell you what your chances of herpes are, but if you've had any unprotected sex or received oral sex, it's possible.