Last night while doing facepulls in my home I heard a sound coming from my shoulder. I thought it sounded like hair being cut by a scissors, my girlfriend described it as a grinding-mortar-in-a-pestle type of noise. it didn't hurt, but this is not the first time I've had problems with this shoulder. I roll the shoulder out using a lacrosse ball regularly twice a week.
What does this sound likely indicate and what can I do about it?