I have been experiencing the severe headaches and occasional nausea, muscle aches, etc. During a conversation about the side effects my husband asked why the dosing of Betaseron was not done according to body weight, as is the case with most medications. Maybe you can answer this question. You raise a reasonable point, that the same unit dose of drug is being dispensed for persons of different body weight. It is possible that some of your symptoms are not strictly dose-related, and that you could have some degree of muscle aches or headaches even on a lower dose.
Some symptoms get better over time.
Discuss some of these treatment possibilities with your doctor. You asked if I pre-medicated with Tylenol, yes I do. You also asked if I tried using a lower dose and gradually moved up to the full dose. The answer to that is no. My neuro prescribed the full dose.