It seems to me that you might have develop some intolerance to shrimps, many people do. The milk it is a good anti-acid that can neutralize it. I suggest you to see an specialist, because my experience tells me (have some friends with it) that it might get worst.
Jesus.
I think you need to see a gastroenterologist. I can tell you from experience that some conditions with the digestive system are just like having a heart attack. A couple of months ago I called an ambulance because I honestly thought I was dying. If felt in every way the same as a heart attack I had in 2007, apart from one thing. I could walk up and down the stairs without the pain getting any worse and without making me pant for breath. Now, at the hospital they ran blood tests, which they would have with you too, and they were negative for heart attack. There are very specific markers they can look for in blood. After further tests, it turned out my esophagus was inflamed. I've felt heartburn before, but this was like a knife being twisted in my chest. Sometimes the pains came on after eating, sometimes not. It was all so random. Anyway, it turned out that I had produced a bit too much acid one day, which is nasty stuff for the esophagus. It has no protection like the stomach lining. There is a sphincter at the base of the esophagus where it enters the stomach, to prevent back flow of acid, but this had weakened due to too much acid. They gave me some strong anti-acid meds (Omeprazole) and it took about 2 weeks, but it did the trick. I didn't realise the food pipe could be so painful and give so many other symptoms. My heart was racing, I was sweating, I felt odd tingling in my arms and legs and I felt light headed. It could even be worth some over the counter anti-acid to see if it works, I don't know if you have Gaviscon there, but that is very good. I would take it when you wake up, and then when you go to bed. I was told that when the esophagus is inflamed, food going down is very rough against it, aggravating it. Milk is very gentle and cool, so it won't have the same affect.