Left side Neck pain. Serious or normal?

Good evening doctor recently I am going through breakup and I am in so much pain. My hunger sleep and thrist almost gone. After that some of my friend suggest me for spit tabacco (khenni). I used spit tabbaco for 7 days continue. After that I feel something in my throat and reduce saliva because of spit. I have no any problem like swallow food and water or swelling but problem in stuck saliva. Feeling like throat is dry and when I drink water acid is coming out from the throat acid reflux. Today I feel left side Neck pain it is due to postural or neck cancer???. I search on internet it shows terrifying result. No any other complications like fever, cold but some scratchy feeling in throat. And sometimes pain under the trenches means under the throat. What should I do??? It is something serious or normal??? I am in lot of confusion.