Lactic Acid causes soreness? Not really.
There are a lot of misconceptions about what causes soreness. For many years sport scientists have explained that it is a by-product of over use/intense exercise and that an accumulation of lactic acid is the primary reason why we experience soreness. Luckily now there are plenty of studies published dispelling the myth that soreness has anything to do with lactic acid. Below are some references and further explanation why its not.
"Lactic Acid is actually a fuel, not a waste product"
https://www.nytimes.com/2006/05/16/health/nutrition/16run.html
“Lactic acid is actually a fuel, not a caustic waste product. Muscles make it deliberately, producing it from glucose, and they burn it to obtain energy. The reason trained athletes can perform so hard and so long is because their intense training causes their muscles to adapt so they more readily and efficiently absorb lactic acid.”
Here is a great summary by Dr. Bruce Gladden:
“For much of the 20th century, lactate was largely considered a dead-end waste product of glycolysis due to hypoxia, the primary cause of the O2 debt following exercise, a major cause of muscle fatigue, and a key factor in acidosis-induced tissue damage. Since the 1970s, a ‘lactate revolution’ has occurred…… It now appears that increased lactate production and concentration as a result of anoxia or dysoxia (hypoxia) are often the exception rather than the rule. Lactic acidosis is being re-evaluated as a factor in muscle fatigue….Lactate can no longer be considered the usual suspect for metabolic ‘crimes’, but is instead a central player in cellular, regional and whole body metabolism……”
https://www.bostonsportsmed.com/2013/08/the-lactic-acid-myth/