Hi and Welcome Rosey4
I had terrible period pains with sequential HRT and actually came off HRT at 49 because of these pains and the scares that were going round at the time. I went back on HRT again after 3 dreadful years of meno symptoms and tried various HRTs with no success and finally had a Mirena coil fitted and used Oestrogel for the oestrogen. The oestrogen isn't the thing that gives you the pain, it is the progesterone that makes your uterus shed it's lining and keeps it healthy that causes pain. If you have a Mirena fitted and use Oestrogel or an oestrogen patch you will get a little break through bleeding for a while but after a few weeks this should stop. I didn't get any nasty pain with the Mirena (just rather uncomfortable having it fitted). You say you went into hospital to have your Mirena fitted!!Did you have an anaesthetic ? If you did you were very lucky - the NHS don't do this - they just fit it with a bit of local anaesthetic internally.
Once you are post meno ( 18months to 2 years past your last period0)you can have continuous HRT but even then a Mirena and Oestrogel could be the best option.
Others may be along soon with advice.