Do a search on this site re: PIP. should provide you all the potential answers.
Any juice with ethyl oleate as a solvent gives me a similar painful reaction, hard to bend the leg, and swelling. Very painful, especially if you keep doing the same vial for this whole cycle. This is why I homebrew now, because you have control over the oil, and solvents(plus its much cheaper)
Oh yeah avoid the quads, use the glutes as much as possible, maybe the delts too.