Went up to oil chains on jaw belt and saw that belt that feeds tyrock screen had a lot of build up. Locked out equipment. Got a pick ax and scraper. Walked down the 1-1/4"" belt. Scraping the sides of the bin. Used pick ax in corners. Crouched down low and swinging pick ax and got it hooked on an angle. Arm stopped mid swing/felt like a stabbing in front shoulder