If there's a test, I've probably had it lol. Sigmoidoscopy, colonoscopy (removed 3x adenomas - 2x with the hot snare and 1x with cold biopsy, and took further biopsies), endoscopy with five biopsies, cystoscopy (that one's like a sigmoidoscopy, but up the front - and yes you're awake...), EMG muscle test, you name it.
I need colonoscopies every 10 years now for surveillance, to make sure the adenomas/polyps/anything else doesn't grow back. I had light sedation for the colonoscopy. It was mildly uncomfortable when they pumped in the air and when they turned to go across at the top (someone above said the same), but it wasn't actually outright painful and I wouldn't worry about having another. It's one of the 'easy' procedures I've had in the scheme of things. It just feels weird with brief uncomfortable/briefly slightly painful bits. Think 'Ooh! Oh, it's gone already' rather than 'ARGH!'. I had inflammation and other issues at the time, so I'm sure yours won't even be that 'bad' OP. Really, don't worry. If I had to choose between a colonoscopy every week, and one of the other above procedures, I'd skip to the colonoscopy clinic with a smile on my face (ooh er). They're that 'easy'.
The prep is a nuisance, and 2L of fluid was hard to take (especially when I hated the flavour/texture). They don't use Movicol type stuff anymore, here at least. They use something else, I forget exactly but it was akin to an 'overdose' of Vitamin C or similar that prompts you to need a liquid poo every hour for 3-4 hours, then nothing. Then your next drink, the same again, and you're done. Not 'that' bad, just awkward and... well, inconvenient...