Hello and welcome to HCM
The abdominal pain
taht you are mentioning could be due to muscular pain
due to muscle strain
during the act of sex.
Howevr, you should go for an ultrasound abdomen to rule out any other cause of abdominal pain.
It could be due to an unrelated cause like indigestion, gastric ulcer or injury to any organ in the abdomen.
Try some muscle relaxant- serratiopeptidase
preparation and avoid muscle straining for some time.
Thanks and take care
Dr Shailja P Wahal