Hello.
I should answer in Japanese, but due to system restrictions, it will be in English.
The problem you are asking about is most likely something called "touch current." This is a phenomenon in which a weak electric current flows through the human body when you touch a PC while it is charging.
There is a similar question in the Japanese version of Microsoft Q&A below, so please refer to it.
https://learn.microsoft.com/ja-jp/answers/questions/2319607/ac-surface-laptop-4
Please contact Surface support and ask if it can be repaired.
[How to get service or repair for your Surface]
Thank you in advance.