I don't think a generic hormone test will show a problem. Doctors tend to use a broad brush when looking at hormones. Besides, it would be your hormone condition during the time after sexual activity. My bet is it has more to do with increased blood pressure and exertion or the fact that a veritable cocktail of brain chemicals, including oxytocin, is set loose in men. This may cause an over-production or deficiency of needed neurochemicals, neurotransmitters, etc. that a concussed brain is sensitive to. Sexual dysfunctions of all varieties are not uncommon with PCS.

If you don't figure this out, just be glad you can enjoy sex. Many with PCS struggle to enjoy sex.