i have done quads, shoulders, biceps, and triceps on myself, not flexible enough to reach ass, traps, or lats. id have to say biceps was the most painful, 1inch needle, 25guage with some tren100mg/ml, ouch. :-/ wasn't too painful the day after, the MOST painful was suspension 1cc in my quad, i couldn't manouver for like, 5 days afterwards, and then a week later i was still sore.
dj