Anti sickness injection

Stacey
After my labour I had a anti sickness injection in my right thigh.
 I'm now 4 weeks and 2 days postpartum and my thigh still hurts, it seems to be the muscle exactly where they inserted the injection.
I can't kneel down on the floor or get up from a sitting position without putting my weight on the left leg and holding onto something to get up.
Has anyone had this injection 
experienced this? I thought it would have got better by now. TIA x