Am I wrong to be bitter towards my best friend for this?

Your friend is an angry POS loser who would rather spend taxpayer money whining and complaining rather than making any effort to help himself, he is a waste of space. You need to avoid him, the only person you will ever have any control over is yourself. As to your post bypass pain, you need to see different doctors until you find one willing and skilled enough to give you a viable diagnosis. My neighbor went through all that but is better now, but you need to take control of your care by finding a competent doctor, you can and should be helped, no one should have to live with chronic pain.