Behind ear, side head pain (left) Of te)

Pain behind ear,side head and sometimg in shoulder(only left side).pain sometime go away and comes again.feel one tiny cracking sound in ear when eating.Consulted ENT he gave me calvam625 for 7 day (3times).after that pain was little reduce but after some day it is there but little lower than 1st time pain.I already did usg of my left ear area as doctor the said.fictir told me that report is ok,there is no completely.now doctor gave me swich 200,I will start it from tomorrow.but I m really worried about it..don't know what should I do why pain comes repeatedly.please help.is this any dangerous deases? What type of doctor I should contact now? (Note: Some years ago I did root canal one of my teeth(left side),sometime feel very tiny pain,,but I forgot to mentioned it to my doctor.is there any possibilities that it is because of te)