There has come a sprain on my foot mysteriously through the night :), not able to walk comfortably.
Also, is there any other general grammatical mistake in the above sentence?
Although it is grammatically correct to use "sprain" as a noun, which you are doing, it is much more commonly used as a verb, i.e., "I sprained my foot mysteriously in the night."
Your sentence gets the point across, but you are missing a subject for your clause after the comma - who is not able to walk comfortably? If I were writing this sentence, I would say:
"My foot seems to have been sprained mysteriously in the night and I can't walk comfortably"