I don't have Fibro but I understand the pain - have you tried using a TENS machine for your pain? I swear by mine!
One thing that is often misunderstood about the electrodes is that they go
either side of the pain... if you put the electrodes
on the pain it'll burst the painometre and be the worst pain you've ever felt by a
very long way... take the pain you feel every day and multiply it by 100 - that'll be what it's like if you put them on the pain, but if you put the pads either side of the pain and slowly increase the intensity, the pain will be gone in less than 15 minutes and will stay gone for as long as you wear it!
If you've got a pacemaker or epilepsy then don't use the TENS machine but otherwise give it a try and see if it helps you? Your GP might have one you can borrow for a while to see if it helps you or you can get a very basic machine on Amazon for less than £20. The one I've got cost me just over £75 on Amazon and I wouldn't be without it now! The only ongoing expenses are batteries and electrodes but they don't cost the earth and to be pain free is priceless!
