Quote (-=vasya=- @ Feb 13 2015 05:14am)
well i though you only get them when your muscles grow too fast
idk, early when I began lifting I would have alot more emphasis on my left pectoral than my right when benching/doing any pressing movements, after awhile it caused my right pec to be much smaller and my left one to get a huge strech mark that (luckily) isnt too visible but goes deep into my armpit, and i noticed it getting larger as i kept lifting.