Swelling underneath collar bone going to armpit area for 2+ weeks, had CBC and ultrasound done, both came back clear. No redness/discoloration. Help?

Different imaging. The type of physical finding is often times better visualized with CT or MRI. There are many structures in this area that can be a cause for this swelling. Especially lymph nodes. Muscle injury blood vessels all are there. Ultrasound is of limited value for an initial investigation especially when you are not sure of the cause. Talk to you doctor for more help.