Hello. Have you had an injury in the past? Weakness indicates either a muscular/tendon or Neurological problem. At your age, unless you have a previous injury, it is likely to be rotator cuff tendinopathy or tear. Please see an orthopaedic surgeon for full assessment. If there is no tear (you may need an ultrasound), then treatment is conservative with physio +/- injection.
Answered2017-02-20 11:41:53
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