Thawed precooked shrimp in the refrigerator for 4 day is it still ok to eat?

It might be. So much depends on the quality of the shrimp before it was frozen and how it has been handled since. You will have to make the decision yourself. If it isn't slimy, watery, or mushy and doesn't have any off-odors, it might be OK to use. In reality, it is getting towards the end of how long you should keep it.