Thanks for your question on HCM. In my opinion it seems muscular pain only. But in intermittent pain , we need to rule out cardiac cause first. So get done ECG first. If this is normal than no need to worry much for cardiac cause. And multivitamin will not cause any harm. I advice you to follow these steps along with multivitamin for better symptomatic relief in muscular pain. 1. Avoid heavy weight lifting and strenuous exercise. 2. Avoid bad postures in sleep. 3. Take good painkiller and muscle relaxant. 4. Apply warm water pad on affected site.