Welcome to HCM. The sound you are hearing arises from the Temporo-Mandibular joint which is situate just in front of the ear.It is this joint which tends to dislodge the ear wax
formed in the ear canal
.What you are scratching would be the neck of the mandible,the movement of the cartilage
at the TM joint would be passed on to the eardrum
and ear canal and any dried ear wax would feel like a scratching/rubbing sound.I do not feel there is anything serious,a ENT check and a TM joint examination will reveal any problem.