I too was experiencing these side effects. I went through one pen and suffered. About 10 days in, I began to get hip pain, leg muscle pain and weakness, knees hurting, shin ones hurting and calf muscle pain. Even had issues with the tops of my hands. My Dr. suggested stopping for a week and resume the medication. If pain continues then possibly switching medication. It's been two weeks and feel much better already. Don't think I'm going to go back even if I have to "take my chances".