That doesn't sound crazy at all. It sounds perfectly normal for many smokers.
Smoking became such a huge part of all of our lives that it is hard to imagine life without cigarettes. All of us here made changes in order to live a smoke free life. For some, those changes were more difficult than others, but with time we see that life as a non-smoker is worth the early stress and struggles that can come with quitting.
As far as your lungs feeling tight and painful whenever you get a craving, I'm not sure how common that is. Still, you are doing incredibly horrible damage to your lungs and the rest of your body when you do light up so I could see that being a reaction.
Stick around this site and read up on experiences others have had in their quits. You will see that a lot of the anxiety you are feeling is normal and it is possible to fight through it and eventually lead a healthier, smoke-free life. Heck, you are already on your way. Congrats on your third day smoke free. Those first few days are the toughest but things do get better as long as you don't light back up.