Hi. You have not mentioned your age. Your upper back and neck pain could be acute or chronic. If it acute could be from a muscular strain of the upper back and neck muscles. If its chronic could be from the cervical spine
like cervical spondylosis
or a disc pathology. Sore throat
and difficulty in swallowing could be due to a upper throat infection
and rarely due to various conditions of the food pipe. I would suggest you to see a ENT specialist
regarding this. For your neck problem do take care of your neck posture specially while sleeping and some anti-inflammatory drugs with muscle relaxants if u are not allergic to it. Once relieved of your neck pain you can perform some neck and upper back exercises which will help strengthen your neck muscles. Do drink lot of water. Thanku.