Why is there severe pain in thigh bones during periods?

The question of : Referred pain can be difficult. If recent then may have more going on. I would start with the pill to limit menses but it sounds like you have what we call dysmenorrhea, painful periods. If you have bad mood symptoms, especially insomnia and daytime fatigue, the pain is generally worse; not excluding a physical diagnosis such as uterine enlargement or endometriosis, but pain is linked 2 mood.