I had my surgery 1/3/18 and I felt the same as you. It gets better. I learned to slow down when eating even that small amount. Set your timer for the 20 min, it makes a huge difference I no longer get that chest pain if I do that. I find that if I eat something too fast I will get the feeling you described. Also with time you will be able to drink more water. I can drink a cup of water almost regularly now. It's a learning process, give your body and mind time to process all the new changes