Thanks for all these additional details.
This can be a case of Lipoma, It is a non-cancerous tumour that is made up of fat cells. It slowly grows under the skin in the subcutaneous tissue. Its exact cause is not known.Torso, neck and shoulder are the most common site.It is non cancerous.It is diagnosed by physical examination by your doctor.
Other possibility could be- Cyst.
These are benign growths that can occur under the skin anywhere on the body.
Such cyst are round lumps and can be felt just beneath the skin surface. They are very common. Usually they are small of the pea size but sometimes they slowly get bigger over many months to become a few centimeters in diameter. Associated pain, could be related with inflamed cyst.
You can take tab. Ibuprofen 400 mg from the counter. It is available as OTC(over the counter) without prescription and will relieve the pain.
Also if the condition doesn't improve , then it can be removed by a simple operation under local anesthesia. In such case a small incision is made over the cyst. Typically, the cyst can be easily removed.
I am sure, this is not related with any serious issue. Please don't get panic.
Good to hear that you have got next week appointment with your doctor. They would clinically examine it and advise appropriate line of treatment.
I hope this helps.
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