lump in shoulder muscle

Hi. My upper shoulder muscle, about two inches from my neck on the left side, is very weird right now. For about a year, I have had a lump in my muscle. It does not cause me pain or severe tension, although it does quite often feel dense and it makes my upper back very stressed. Like I said, this has been here for a year. I have been doing yoga during the time I've had it and even tried massages. Can anyone help me?

I think anytime you have a lump on your body for no reason you should ask your Dr. to look at it.