First of all if its due to heavy weight lifting and shirt duration it might be just musculoskeletal pain.
Which will be subsided with muscle relaxant and pain killers tablets. Avoid heavy weight lifting for week at least.
Secondly, if you find any swelling or buldge In left groin or scrotum then it can be inguinal hernia (less likely according your short duration of history)
Next Steps
Start tablet Myospaz forte twice a day after food for 5 days.
Health Tips
If it doesn't subside better consult surge atleast once to rule out hernia