When considering taking Myoril 4 mg Capsule (Thiocolchicoside) for pain from your head to your arm, it's important to understand a few key points:

• What Myoril is: It is a muscle relaxant used to relieve muscle spasms and related pain.

• Nature of your pain: Pain extending from the head to the arm for a month could have various causes, including nerve issues, muscle strain, or other medical conditions.

• Consultation is essential: Because your pain has lasted for a month and involves multiple areas, it's important to see a doctor for a proper diagnosis before starting any medication.

• Potential risks: Taking muscle relaxants without proper evaluation may not address the underlying cause and could have side effects such as drowsiness, stomach upset, or nausea.

Please consider scheduling an appointment with a neurologist or orthopedic specialist who can assess your symptoms, possibly order investigations, and recommend the most appropriate treatment for your condition. If your pain worsens or you experience other symptoms like weakness or numbness, seek medical attention promptly.To narrow down potential causes, we will need some more information.I understand you've been having pain from your head to your arm for a month. To give you the best advice, could you please tell me your age and gender?