Hi Spacey! Welcome to Crohn's Forum. The people are all very kind and supportive here, and they'll be willing to lend you a listening ear and offer you advice whenever you need it. My inbox is also open to your messages 24/7.
Before I begin, let me do a brief introduction of myself. I'm CYY, a 16-year-old female who has been recently diagnosed with Crohn's about a month ago. I'm currently on Modulen IBD as part of my EEN treatment, and if all goes well, I may start Azathioprine in mid-February.
I can totally relate to the joint pains that you're having. On several occasions, I do feel like a 60-year-old when my lower back, hips and knees hurt like crazy when I sit down or stand up. I believe joint pain can be an extra intestinal manifestation of Crohn's, so I'd get that checked out if I were you.
I'm really sorry that I'm unable to provide much advice since I suffer more from diarrhoea than constipation, but I'd like to wish you all the best for your colonoscopy all the same! =D
(If you're looking for advice on how to deal with colonoscopies, I've shared my experiences on this other thread:
http://www.crohnsforum.com/showthread.php?p=961882#post961882. Be sure to check it out!)