sounds like my threads 4weeks ago, lemme guess, you're using test. Yes it goes away as soon as your body adjusts to it, remember you are putting a foreign substance in there. As far as the ass hurting, comes with the territory sometimes, i had the same probs. Some tricks to avoiding is make sure you have the right location which is the upper-outer part of the glute, after you take the injection rub as hard as you can on the injection site, i mean rub! that helps a lot. Another thing you can try is running the syringe under hott water for a couple minutes with the test in it so it helps dissolve a little better.