What Causes Persistent Pain And Weakness In Elbow?

About a year and a half ago, I fell backward on the ice (2 days in a row) landing directly on my L-elbow with much impact. It hurt terribly. My elbow bruised (3/4 of my arm) and I had a protruded puffed area on the elbow. I did not go to the emergency room. Finally, 3 months later when the pain still had not let up, I went to the Dr, had an x-ray done which did not show a fracture and was sent for an injection, with little help. 9 months I continued to complain, finally had an MRI, which showed an effusion and a small tear of some type, which the Dr stated explained why it was sore, but never went any further than that, other than to offer another injection. That injection hurt for 3 days, but then gave me relief for about 3 months. Today, 1-1/2 yrs later, I still continue with the pain and weakness. My arm trembles if I pick up something, such as a cup of coffee to take a drink. I still cannot lay on my side with d/t pain in elbow, I have to keep it slightly bent and upright on a pillow laying flat on my back. The pain feels the same today as it did when I fell over a year and a half ago. I am scheduled for a 3rd injection this week. I m frustrated the pain/weakness does not stop. I do not favor my arm/elbow. I go on with my daily tasks. Thank you -KG