I had really bad sciatica for 18 months, my GP even sent me to a Pain Clinic where I had Acupuncture. They suggested that my nerves were misfiring even though the original inflammation had died down.
I have also trained in Swedish Massage. I used to massage my own body where the pains were bad and where I could reach them.
HOWEVER, your current situation sounds extreme and I wouldn’t recommend any self treatment UNTIL you have spoken to a professional. With so much pain, there will be a chance that the wrong treatment could make it worse.
If you get the Ok from them, then gentle massage may help because you can do this daily instead of only seeing your Osteopath weekly. You can ask if hot/cold treatment helps. (Gel packs)
I don’t believe (my person opinion) that massage needs to be firm to help (though with a professional it can do wonders). I believe sometimes it just helps because it causes the touch and sensation receptors in the skin to activate and just sets up a non painful sensation in the same area where the pain is. This effect can be done with the most gently stroking of the skin and no massage as at all. This is why it’s called The Healing Touch.
I rub and massage my head when I have a migraine, partly just to distract from the pain signals inside my skull.
I agree with your first poster, and although I am a random on the internet telling you my solution, please seek expert help before doing anything.
I do hope things improve soon.