The medical details that you report indicate that the pain during sex, constipation and stomachache probably originate from the hernia surgery. During intercourse, the abdominal muscles contract. The weak spot that remains where the hernia was previously located might again cause pain. Furthermore, the motility of the bowels may have been affected after the operation, depending on the type of hernia. No data was given about the type of hernia, so I'd suggest that you follow up with the supervising surgeon to report your symptoms and to follow up with questions about recovery time and possible treatment.