Welcome to HCM.
It might be due to excessive pressure on left side due to unequal constant sitting.
It usually occurs after long drive.
You have to take muscle relaxant
and therapeutic dose of vitamin b12
for at least 7 to 10 days.
Avoid any exercise at present till get complete cure.
Local application of ice and any nsaid gel will be helpful.
Consult orthopedician for further diagnosis and medical management.