hey guys, just wondering about the laying tricep extension. I have been steadily going up in weight in it, aiming for between 6-8 reps. But when I am finished a set and get up I feel momentary (5-10 seconds) pain (something like intense lactic acid buildup) all in my upper chest. is this normal? I also feel that I am arching my back too much and possibly using it to support the heavy weight.

This leads me into my second question. I think I have heard somewhere (Arnold I think) that for tricep excercises, you should do more reps, 12-14 perhaps. is this true? maybe my problem? thanx.