I dont want to scare you but my husband had a lump on his neck as well. Blood Results came back normal, but he dr had him go for a CT scan which showed something abnormal. We had to go to an ENT for a biopsy but he ended up having squamous cell carcinoma and is currently receiving treatment.
It could be nothing, it could be something; If I were you, I would make an appointment with an ENT to have this looked at.