Indeed I understand all too well from where you are coming Nanooka,it is certainly not the most pleasant of procedures.
I have already lost half a colon and quite a lot of gut.....cancer related,whilst my Mother died from colon cancer and my sister also had a large cancerous tumour removed.
The earlier colonoscipies initially were carried out under GA.
This was halted as deemed too dangerous though I rather believe it is to save having an anaethetist on board....... the NHS cutting back again.
I had one prior to Christmas 2017 and then another 4 during the year............the initial one was virtually painless,I opted for no sedation even.
But thereafter they became increasingly painful.
One involved a gastroscopy at the same time.
Because of long standing issues I tried my best to cope but when the Endoscopist found a polyp and then lost it..........saying he would have to repeat the Coloscopy.......it really was the "last straw"........however this was done and said polyp removed.
Because of being Hospitalised with other serious problems I have had 3 appointments cancelled, so it will be another 2 weeks before I eventually have the results of all colonoscopies plus latterly a CT scan.
However I think you really need to point out your pain threshold to both your G.P and to the Endoscopist,hopefully they will take your fears on board.
When these are requested fairly frequently, of course the fears are there and surely it makes sense for the patient to be at ease during such procedures .......if they wish to obtain a clear picture.........which surely is the whole point of these procedures.