What Is A Soft, Movable Lump On Right Shoulder Suggestive Of?

Just found a soft 2 cm soft lump on my right shoulder at the juncture of where collar bone meets shoulder. It is moveable and actually dimples like cellulite when moved. It does not hurt although, I have been having pain in that shoulder on and off for the last few months. I have had lipoma s before and even cysts. But this just came up so suddenly. My greatest concern is that I currently have low risk ( score 1) MDS and that it could be changing things although, God has been good and my ANC , white counts and platelets have been good. Great with the last check. My ANC was 4000 when It had been all the way down to 386 and my WC was 7000 ( up from 1200). So...not sure where to begin. With my MDS Dr or my PCP. I also have been having a tightness in my lower throat, burning and tightness just below thyroid level. Feels like burning on or near the vocal cords. some raspiness...but, I am not sick . No fevers however for a couple of days Ive had some difficulty swallowing at times. ( I actually thought I had just gotten choked and the pain i was feeling was just residual irritation..but, its not going away. ) Any idea s. Oh the other concern is that I had Melanoma in 2005 on my right thigh but nothing new there with last skin check. Got any ideas?