went to see an Oriental Doctor [use "an" instead of "a" because "Oriental" starts with a vowel sound]

I came to Korea to enjoy Luna New Year's vacation, which is called "설날" in Korean.

And I did many things in a day, like getting a haircut, shopping, reading, and going to see a doctor. [All the actions in your list should be in -ing form.]

Ironically I went to see an Oriental doctor the day after I came back from China. ["Oriental" should always have a capital O. it can be "the day after I came back" or "the day after coming back"]

The doctor pressed my left wrist then said I have too much stress, and pressed my right wrist then said I have a gastritis. [You can say "I have too much stress" or "I am under too much stress" or "I have become too stressed". "gastritis" does not need the article "a".]

I can guess where the stress is from, which is that I had to make a hard decision recently, and I think about that too much.

The problem is whether a patient believes him or not. ["whether" emphasizes that there is a choice between two options.]