How Does Tendonitis Affect The Muscular System Is There A Pain Killer That Does Not Affect Your Concentration?

Is there a pain killer that does not affect your concentration? - how does tendonitis affect the muscular system

I did not heal tendinitis in his elbow. I need a pain reliever that does not affect my concentration, to go before the sport (boxing).
I had this for many years and has recently resumed training after a break of 3 years immediately and elbows give me much trouble.