grinding,squeeking in elbow

whenever I squeeze my fist, contract my tri & push like i’m bench pressing, I get real bad pain at the bottom of my tricep around the back/slightly lateral & above the epicondyle bone. it also grinds like heck.if I don’t make a tight fist or con tract the tri it seems fine. also when I externaly rotate my forearm, I do not exprence any of the above mentioned problems.any ideas ?? BTW, I have had 2 surgeries on that elbow this year. one for tennis elbow & one for loose bodies via arthoscopic means. Thanks