mass behind the ear sounds chronic issue could be a benign lymph
node or lipoma
or a sebaceous cyst. a simple excision will help
pain radiating down the leg. now that might be a simple nerve
pinch or back ache or a kidney
stone if your urine is having blood or you have pain in urination. if not cheers. just analgesia with acetaminophen
And your chest and heavy breathing and worry for a heart attack? had it been a heart attack you would have been here writing this question on HCM. to reassure yourself do a simple ECG and you will be fine.
Regards and cheers