Do you know if the doctor will sedate you for these procedures? In the US, we get knocked out for both endoscopy and colonoscopy..not fully asleep, but a conscious sedation that makes us feel as though we are asleep though able to respond to questions and a drug to make us forget everything afterwards.
Endoscopy requires no prep other than nothing to eat or drink after midnight generally. Colonoscopy, on the other hand, does require prep of cleaning out the colon which, though generally not painful, the cleansing requires drinking a lot of medicated fluid which is very unpleasant tasting and can cause vomiting and abdominal distension until everything kicks in and you have diarrhea for several hours. Once the prep is over with, the actual test of colonoscopy is a breeze if you are knocked out. If you are kept awake and alert, you may have some pain during these procedure.
If you are terribly concerned, I urge you to call your doctor's office and talk to someone about it.