I started to use Novomix 30 and Metformin 6 months ago at 60 units/day, and experienced moderate left shoulder pain. but when I decided to discontinue the Metformin and increase my dosage of insulin to 90IU/day I suffered from severe pain in both shoulders, neck area, stiffening of complete upper back muscles, sleep disorders, severe cough and bronchspasm. When I decided to swith my insulin regimen to Lantus/aspart combination the above symptoms started to subside immediately. In my opinion those side effects were attributable to the protamine in the Insulin Aspart of the Novomix 30. I had no prior sensitivity to fish.