Shoulder Pain. Why? What Is The Small Bump On Neck?

Hi Dr. I hope all is well with you. I am Gaya here from Malaysia. I have been having bad shoulder ache for the past 2 years and went for few check ups in clinic and was given muscle relaxing pills and pain killers. I have no issue carrying up my hands but recently when I have shoulder aches, my whole hand till fingers, neck and head is also aching. I also noticed a small lump just behind my body just under my neck.It has been there for about 4 months now and another small one developed as well. The size isnt big just as big as a pea and no pain. Is this something serious and should I seek further medical treatments?