you know i took my first injection on Mon. last week( 1 1/2cc of test e) and by thursday my ass was swollen like never before. I haven't done a cycle in almost 2 years..but i never remember my injections getting this sore.
Don't think filtering will help. Just got done with stealth cyp, masteron, prop and EQ. The only one that really hurt for me was the prop (it nearly cripples my entire leg starting 2 days after injection, for about 2 days). But pain was not as bad if I didn't shoot my quads and diluted it by mixing with EQ and masteron in the same shot.
I really don't think sterilizing is necessary, but if it makes you more comfortable, then it certainly can't hurt. Just don't burn it. I'd be interested in hearing about your gains when they start showing up. I finished off quite a bit of the stuff recently and I'm completely undecided on how well it works. Not saying it doesn't work at all, but I wasn't that impressed with the stuff, given the amounts that I took. At first, I thought it was really starting to kick in nicely, but then it seemed like nothing happened after that. Pretty certain it wasn't my diet/training/rest, I'm always very careful with all of that.