It is definitely hard to make yourself continue something when you know the result is pain. I had exploratory knee surgery last year and of course, nothing was fixed so I have been battling it for a while now. Even just walking is huge, but after surgery I have learned a little more about my knee and what it can take. Before surgery, I was just walking as fast as I could tolerate pain wise and I would do it for 30 min straight. Since surgery, I have broke it up into 6-10 sessions throughout the day, no more than 20 min a piece. Along with reducing the time, I realized I don't have to walk that fast right now. I am going maybe half the speed I previously was and the pain has been minimized quite a bit. There is still some, but definitely an amount I can handle. And by getting the little bits in here and there, I am still getting my workout in (maybe not as intense and I would like, but it is better than nothing! Just keep in mind, every little bit will help you lose weight and as the weight comes of, hopefully the pain will be less and less. It can only get better from here.