Hi Peterspots - I'm afraid I've experienced this really unpleasant soreness in the urethra on and off for many years. I doubt the cystoscopy would have made it much worse but this soreness is often related to vaginal atrophy. As Hurdity explained, there are oestrogen receptors in the bladder and urethra and as oestrogen declines the whole area becomes more delicate. Regular UTI type symptoms (often with no actual infection detected) are one of the many things we meno ladies experience and local oestrogen is often the best treatment to reduce the discomfort. Local oestrogen helps to keep the whole area more healthy and resilient. I would try Vagifem first as the creams can be a bit messy and when my urethra is sore I find the fillers in the cream can irritate things a bit.
I also find that when I am sore (I feel as though my urethra is actually swollen!!) I tense in my pelvic floor and, whilst they tell us to do pelvic floor exercises, I do find that if I actively relax my pelvic muscles, particularly if I have my feet up, this will relieve the soreness. The other thing to watch out for is making sure you really empty your bladder properly every time - so really relax and sit there until everything has trickled out - again, it's easy to retain urine which can become more acidic and irritate.
The advice about using bicarb in a drink a couple of times a day for a few days is really good. Also make usreyou aren't using anything perfumed on your intimate area - shower, don't bath and perhaps get some vaginal moisturiser (online or at the chemist) that will keep the vaginal area lubricate and healthy. I use a little Multi Gyn Actigel everyday which seems to help.
There is a lady visits MM who has posted about this issue - she has seen a specialist who believes there can be infection embedded in the bladder wall that can only be treated with long term powerful ABs. This specialist believes the overuse of short term ABs for UTIs has probably created bacteria resistance (which is now prevalent for many things). However, many of us do find that he local oestrogen is the key to preventing infection taking hold in the first place. DG x