Hi welcome to Health care magic forum.
Thanks for calling H.C.M.Forum.
You had pain full swelling in the left scrotal sac. since 4 days, since past 4 months it is repeating, after a pain of 4 days it is becoming normal. the pain when it is there is unbearable.
As you describe it appears to be the inguinal
hernia, means a portin of the intestine or fat from the stomach enters into the scrotal sac.
When you consult the doctor there may be no swelling, that is why he missed it.
I advise you to consult a surgeon for diagnosis and treatment , when there is swelling. so that he may not miss it. You may need to have surgery for complete recovery.
In the meanwhile i advise you to avoid
stress, cycling, hard work, straining during defeacation, etc.
Wishing for a quick and complete recovery.
Best regards.