1 1/2" pin should do the trick. I usually sit on the edge of the sink so I can get a good clean shot without moving around alot. I haven't had any problems like that though in a while. Old Sustanon 250 used to swell up my shoulder/ass and feel hot for days after I shot it. Haven't had that problem lately though. It's probably not an issue if the pain is going down after a couple of days. I would always keep some anti-biotics on hand just in case a shot goes bad and the pain keeps getting worse. You sound okay though.