I have neck pain and my throat hurts. are these two symptoms related? what are the common causes of these symptoms?

Too many to list: They may be unrelated but it is impossible to advise on those 2 very common problems over the internet. In person medical evaluation is best if symptoms are problematic.

They may be as : An upper respiratory infection can lead to enlarged & painful lymph nodes in neck making neck feeling painful or just muscular pain or myalgias related to the infection or you could have 2 separate issues occurring at the same time such as an infection & neck issue . See your doctor if the sore throat persists more than a day or you have increasing neck pain just to make sure not a meningitis