Thank you for posting your query on HCM.
Well it may be a hernia
that you are mentioning near umbilicus
which you can consult a surgeon whether needs treatment or not but my main concern is about the lump that you are mentioning on your spine .
As you give the history of shudders across the spine that means some nerve
compression is there which needs to be evaluated at earliest to rule out any kind of malignancy or abscss since you say it is very painful . Consult a neurologist
for expert help as it is a matter of concern .
Hope it answers your query.
Take care .