Agree with HappyGorilla about the possible nerve damage. Which is probably due to a blockage of the nerve paths; weaker and less balanced on one side is usually the result. Doesn't always have to be in the trap area, though most often is. Can be the base of the skull/neck or the shoulder joint it's self. Even an out of inlined spine. If having a small knot/bump, anywhere along the shoulder/trap area, that may suggest a nerve blockage. To the extreme it could also be the start of slight rupture.
What your doing for recovery is good and is a proven method for most people. If a lingering problem, that might suggest a deep tissue massage, by a professional. Sports massage or Rolfing come to mind. Acupuncture (or even acupressure to a lesser degree) has worked for many athletes, for many years. Or even a spinal/shoulder adjustment. Good Luck.
all this advice Dude and you look like shit