In the 1930s , american biochemist wendell stanley observed crystals of tobacco mosaic virus. based on this evidence, stanley inferred that viruses

he inferred that viruses are not living organisms. More recently, some scientists have questioned whether viruses act as living organisms because they can manage to form replicates of themselves.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.