In Work from home process you would not be able to use the right table and chair as you would have used at your office.
This could lead to bad sitting posture while working. Your neck and upper back would have got strained because of your bad posture. That would have initiated your pain.
Next Steps
You can use Volini gel or spray to the painful spot provided you are not allergic. You need to take small breaks between every one hour.
You have to do mild neck stretching, rotation to your shoulders, stand and walk around for two minutes.
Health Tips
These simple exercises will give you good relief but if the pain persists you need to consult a Physician or a Physiotherapist for further evaluation and treatment.