Good thing

Looks good to me, OristarA, except that I would remove the "a" which comes before "good news indeed" because it is not needed.

Thanks Grand Duke.

I'd like to hear more mavens' opinion.

PS. Has the colon after "repeatedly" been used properly?

I have to admit that I'm not sure. I think it looks okay, but probably better waiting for someone to confirm.

Okay.

I feel using two sayings in the same short paragraph sounds a bit awkward. Do you agree with me? If so, how to make the para vivid by changing one of them to a proper word?

Not sure about the colon either, but I would remove the comma between saying and repeatedly.

Possible alternative to the colon, and with Einherjar's suggestion about the comma:

Elated, Mr Chen looked like a child, saying repeatedly "Yes, good news, good news indeed!"

And maybe I would write "Mr Chen" instead of "Mr.Chen". Using "Mr. Chen" is perfectly okay, but in everyday usage the "." is not often seen.

This morning he saw his doctor, and was given a clean bill of health.

Hearing this, we immediately congratulated him, saying that was a good thing, good news indeed. Elated, Mr.Chen looked like a child, saying, repeatedly: "Yes, good news, good news indeed!"

Oristar, the colon is correct, but strictly speaking, the succeeding remarks, being a quote, should be in quotation marks. However, a common usage is arising in which it would be as you had written it--that is, a colon followed by a quote, without quotation marks. That is a casual usage, however, not the formal method.

Thanks.

But the question is that the quotation is indirect. Of course it is perfect to put a direct quotation into quotation marks.

Here I am not sure whether using "long ago" is proper:

Seeing that we were puzzled, Mr. Chen went on to explain that he has had a vein thrombus, and was in the hospital for two months not long ago.

Perhaps "recently" would fit the bill?

I'm afraid "Recently" sounds to close to the day of "getting the clean bill of health".