Going Down Stairs With New Bi Level Glasses. Looked Down

going down stairs with new bi level glasses. looked down to my feet and misjudged my perception.
grabbed the rail with both arms mostly right arm to catched what I felt like a possible fall. hurt my
right arm muscle or thought my shoulder. still is very sore. no bruising anywhere. painful when extending right arm only bicep muscle. laying on floor on my back right arm does not reach flat on floor (back of right
hand)