Can overstretching your arm and neck cause artery dissection? if yes, would pain in the area be the only symptom? worried because i overstretched my arm looking for an object and now my neck/shoulder hurts?

An artery dissection would likely cause an acute stroke. Since you typed this after the movement in would say you did not have one,?

Perhaps you have injured your shoulder or even neck. This maybe a transient strain but could represent more lasting issues. An arterial dissection is highly unlikely. See your doctor, get examined, and do appropriate testing, and treatment. Physical therapy may reverse your issues.