What could this injury be?

I know, go to my gp, and in another month I might. But having suffered and healed from several tissue injuries over the decades, I am not at that stage yet.

I am not looking for a diagnosis more has anyone here had this and healed.

Context:

Yes you can laugh.

A couple of years ago on the way to a consultants research project mri (hence gp probably does not have nhs access), brand new on cancer drugs, I was walking along a hospital corridor (the one linking the JR for those who know it) and my shoulder hit a supporting pillar. That jerked my shoulder back, but my forward momentum continued and I really hurt my right side belly area.

Time moves on, it becomes an occasional problem that I lived with.

Realising that I now have basically no fitness anymore I have been using ring fit adventure on lowly level 4 (out of 30 difficulty levels) and after 9 sessions my side went.

Getting off the loo became a swear fest, turning sideways hurt to high heaven and even sometimes walking down a curb hurt. A month later (ie now) it has largely healed.

Sometimes I feel it later in the day, and have just restarted ring fit adventure on level 2 with more off days. Lying in bed ‘cures it’.

I realise that I am going to have to live with this periodically flaring up, but having just survived 2 years since incurable diagnosis, I would like this time next year (if pneumonia the most common cause of Myeloma death, covid, infection, any other cancer and related cause of death (10% chance of death per the maths over next year pre covid) doesn’t get me) to be somewhat fitter again.

I finally seem to be losing weight again after following the advice in the book of a Bariatric surgeon (he did write that it would take time to start using his method), evidenced by the fact that I recently fitted into a shirt that my belly bulged the buttons open a bit the last time I wore it.

So, bearing all that in mind, anyone else here living with or fully recovered from a similar injury? Hopefully caused in a less stupid way.