Top of my left arm trembling/spasaming been going for over 2 days now i have had a cold/virus for the last week but now have horrendous headache?

Left arm spasm: Would check for strep/ mono . Sometimes pharyngitis strep or others can cause muscle tightness in trapezius which is the big muscle of your upper back and neck I would also be concerned about a peritonsillar abscess/ sinusitis and TMJ dysfunction which can cause upper extremity dysfunction . Would follow up with MD/ ER/ urgent care today