Is A Red Mark On The Neck Post An Injury A Concern?

Hi my son fell on left side of body that I could see he had a red mark on his left side of his neck above the collar bone near the base of his neck he has full range of movement doesn t cry or full I can touch collar bone no fuss he laughs must tickle he can raise his arms over head and doesn t slow him down at all I only notice at certain position he fusses a bit when he put pressure on his left arm like in a crawling position doesn t cry no fever but gets tense when pick him up out of car seat under his arm is sore today so not sure what to do