Hello I Have Had Upper Left Arm Pain Which Has

Hello I have had upper left arm pain which has worsened over the last week. At first I thought I had slept awkwardly but now I'm not sure. The pain has traveled to my shoulder area also and I'm unable to lift my arm unaided. I have taken anti inflammatory tablets and an anesthetic patch on area but no relief. What can it be? I'm almost 30, female, not athletic. Thanks