I weigh 150 lbs and am 5"11 inches tall. A few years ago I only dreamed of being able to rep the bar with a plate on each side. Now I dream of being able to rep two plates.

I go in every week and destroy my chest, I do three sets of about 155lbs ( I can only do like 5-6 without breaking form ) on the flat bench, then on the incline, and the decline. I honestly go until I can't anymore, and then usually I do a few more with my spotter. I really kill my chest every week, its sore as hell the next day. Still though I go in every week and the 155 weight bar does not seem to get any lighter.. I also do many other chest exercises once I am done with the flat, incline and decline; I will usually do some dumb bells presses, then some machine or push ups or ropes when I am too weak to continue free weight. I just don't know what I am doing wrong. I thought about putting on more weight, but I can only do like 5-6 reps as it is, and putting on more weight will only hurt my form I feel. I don't know! HELP!