What’s going on with that neck tendon pain and headache?

This condition is usually caused by cold in the head and neck area, which leads to significant muscle tension, and with the gradual increase in tension, if accompanied by poor cervical spine, it leads to slowed blood circulation and gradual accumulation of inflammatory metabolites, resulting in more tension in these muscles and a more pronounced pain. As a result of vasoconstriction after exposure to cold, microcirculation through the muscles decreases significantly, which leads to reduced blood supply as well as diminished venous return, leading to a gradual accumulation of inflammatory metabolites and further aggravation of pain. Headache is caused by the contraction of blood vessels in the head after exposure to cold, and in some cases, vasospasm occurs, resulting in significant pain.