Hello and welcome to health care magic!
I have gone through your question and it seems that you have suffered some kind of internal injury
after that "punch" eight days back. you also have some gastric symptoms like chest/ heart burn and severe pain
in abdomen and the problem is increasing.
I will recommend that : you should visit a doctor at earliest
If I had been seeing you, I would ask for an ultrasound
abdomen, X Ray
chest, ECG, along with some blood tests to make a diagnosis
Please, don't get worried too much but do go and meet the doctor.
Feel free to right back if you have any other concern.
hope this answer helps you in getting well.
Dr. Manisha Gopal