With due respect to opinions of both of you(you and doctor), I would say this needs to be investigated to know what it is. I assume you have declined cat scan or xray due to radiation
, but in that case you can go for MRI
.There are no radiation or any harm in getting MRI done except it is a costly investigation.
In fact MRI is better than Cat scan in such cases.Treatment can be planned only after that.Hope this answers your question.