Severe muscle soreness after PIO

This is my second FET. For first FET I had some pain for a few days following injections (several hours later/next day) but then that went away after a few days. This time, I have severe muscle soreness. Feels like a tetanus shot and makes it painful to walk. I’ve been heating the area before and after and warming the oil. Only difference with this FET is that I’m taking aspirin. I have noticed some more bruising so maybe I’ve been hitting some vessels? Anyone have advice??