### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
I have a lump on the left side of my neck. It is painless and does not seen to get bigger or smaller. I first noticed it about 18 months ago. 18 months ago i was into sleeping on my stomach (which I later found out could really strain your neck). After consistently sleeping on my stomach and therefore straining my neck, I started feeling pain and swelling on the left side of the neck (where the lump is now). Ever since then, i started sleeping normally and the pain is gone but the lump has remained. I am not sure if this is related but i think it is. The lump is painless and between my hairline and trapezius. It is also about an inch in length and width. I can only feel it when I bend my neck down and run my fingers through the area to massage it. It only moves when I massage it and lastly, whenever I would strain my back, it seemed to get worse for some reason. Should I be concerned??? Is there any possible treatments i could do to treat it??? Please help I am so desperate.

### output:

Welcome to Chat Doctor .1. First thing, lying on the stomach will not cause lumps in the neck, it may strain the muscles and cause pain. 2. The most possible cause is lymph nodal enlargement. (could be due to recent infection / underlying medical conditions and systemic causes)3. If you are my patient I would have examined and ask for an ultrasound neck to confirm the nature of the lump, its origin and extensions.4. Depending on the findings an FNAC - fine needle aspiration cytology will help in definitive diagnosis.5. And if any systemic causes - first treat the cause. Hope it helps you. Wish you a good health. Anything to ask ? Do not hesitate. Thank you.