Swollen sides of neck, body-ache, constantly feeling cold. no sore throat, mild upset stomach.?

Cold sensitivity: There are several possibilities, however being more sensitive to the cold temperatures and swelling in the neck suggests the possibility of a thyroid illness causing a condition of low thyroid production called hypothyroidism with an enlargement of the thyroid called goiter. It is imperative that you obtain medical consultation and examination to determine the true cause of your problems.

Viral infection: Sounds like a viral infection but with the neck swelling it would be a good idea to just be seen by a doctor to make sure it isn't a bacterial infection.