I was in the gym yesterday doing a relatively light session which included squatting on the smith machine. It was only about 130kg and I done about 3 sets of 8 reps.
I woke up this morning with an unusual red 'marks' along both of my shoulders.
Is this normal? Or am I doing something wrong whilst holding the bar? It wasn't bothering me at the time and I had a sponge roller thing wrapped around the bar.

The image hasn't done it any justice to be honest, it looks a lot worse to the naked eye! Sorry about the lack of rotation also!
I was just wondering what the cause was really, I'm not concerned about the marks as they aren't bothering me in the slightest, just wanted to know what was the physical reasoning behind them!