Hi ,
How are you doing ?
At this young age with no complications, I can think of 2 possibilities.
1.
Pelvic Inflammatory Disease ( PID ) - infection arising from vagina , after sex. these infection can affect all the structures around
uterus - this includes the tubes , ovaries & adnexa.
2.
Endometriosis - can occur at any age. Bleeding from the uterus during periods is to the exterior , but a small amount of blood enters into the abdomen, through the tube. This blood forms clots & adhesions around the uterus.
Both these conditions around uterus cause increase of blood flow to structures like ovaries , tubes , muscles & ligaments around uterus.
So when ovulation approaches, this cause congestion & pain around the lower abdomen, thighs , lower back .
Both need evaluation by gynecologist. PID needs treatment with anitbiotics & antifungals, both husband & wife
For endometriosis- have Combined
oral contraceptive pills cyclically will stop ovulation & will stop pain & progress of endometriosis. If you are seriously trying for
pregnancy, do have tubal patency evaluated -
HSG or SSG or
Laparoscopy , do rule out tube block , which can hinder your chance of pregnancy.
Hope I have cleared your query
All the best