What Causes Right-sided Shoulder Pain And Growing Bumps?

I have been having pain in my right shoulder for the past week it feels like. I had a massage the Friday before thanksgiving and they went pretty deep so i just attributed it to that. However a few days ago it was referring to under my right pec as well. I just thought that the fascia might be affected as well so i thought my body would work itself out. However, this morning i went to massage the spot that felt sore under my shirt (the past few times I would just do it through the clothing) and noticed that i felt a lot of little bumps. I quickly took off my shirt and looked at the mirror and sure enough there are a collection of bumps with irritated red skin around them in all the places that felt sore! The main place is right on my right lat (most intensely red and biggest bumps) and then they branch out to under my right pec and then the inferior point of my scapula. I ve been looking online and most websites are having symptoms of itchiness associated with the bumps. They are not itchy at all. In fact, they feel more like a bruise and ache/ tingle at times. What could this be and how do I go about curing it? Please let me know!