When lactic acid builds up it causes what?

Lactic acidosis. Muscle ache, burning, rapid breathing, nausea, stomach pain: If you've experienced the unpleasant feeling of lactic acidosis you will remember it. It's temporary. It happens when too much acid builds up in your bloodstream. The most common reason it happens is intense exercise.
The symptoms include a burning feeling in your muscles, cramps, nausea , weakness, and
feeling exhausted. It's your body's way to tell you to stop what you're doing. The soreness you sometimes feel in your muscles a day or two after an intense workout isn't from lactic acidosis. It's your muscles recovering from the workout you gave them.