Can you please tell me if carotid dissection artery pain is constant or intermittent? I have pain in front, right side of neck and mild headache

Likely to be more. constant than to come and go. Neck pain & headache are common problems, though, & unlikely to be carotid artery dissection. If you've had neck trauma or have neurological symptoms (i.e., vision changes, ringing ears, taste changes, facial weakness) you should see your doc asap. Also follow up if it persists or worsens since only an exam can diagnose the problem.