I had cortisone injection on 29 dec my tendons are now imflammed in the foot is this normal?

Why were you given . The cortisone shot? Which tendons are inflammed? It is possible you hd tendonitis and that you still do, iy is possible to get a steroid flare but that should of resolved by now. It is possible there is further injury or a new injury. You really need to follow up with your doctor.