Why do I get sore a day or two after hard exercise?

I finally had the time and guts to go to the gym after taking some time off vigorous exercises. And I feel very sore after. I almost wished I had not done the workout. So why do we get sore a day or two after performing hard exercises?

Soreness after working out

Hutchinson explained that "it is not the low-grade persistent muscle spasm or the accumulation of lactic acid that causes soreness after exercise. Most researchers now agree with the theory was first proposed over a century ago that blames post-exercise soreness on microscopic tears in your muscles. But that leaves an important mystery: if muscle damage is the cause, why does the pain peak 24 to 48 hours after you stop exercising?" (61). 

According to right as rain fitness blog, "the pain that you feel that leaves you waddling around and can feel even worse two days after a workout is a phenomenon called DOMS (delayed onset muscle soreness). The harder you work out, the more likely you are to be sore afterward. You feel the burn after because your body is going through the repair process, rather than the damage itself.

I would spare you the science. But to put it simply, "you have done the crime, you will have to serve the time. The pain results from muscle damage, and once the workout is over you cannot "undamaged" the muscles, despite the promise of various lotions, creams, and pills. The good news, though, is that the damaged muscle comes back stronger once it is repaired. In fact, without this damage, repair cycle, you wouldn't get any benefit from training. So ideally, you want your workout to fall in that sweet spot where you are doing enough microscopic damage to stimulate adaptation, without doing so much damage that you have to skip the next few workouts. As you weed out the weak muscle fibers, you'll become less and less susceptible to DOMS to get this protective effect. A little moderation when you're getting back into workout out or trying a new exercise can allow you to avoid DOMS entirely" (Hutchinson, 62). 

Right as ran blog suggests the use of massage, foam rolling, or an ice bath to help alleviate the bath. I hope you are still looking forward to your next workout after reading this. Remember that the benefit surpasses the burn.

References

Hutchinson, A, Ph.D. "The Physiology of Exercise". Which Comes First, Cardio or Weights? edited by Alex Hutchinson, Harper Collins, 2011, pp. 25-27

https://rightasrain.uwmedicine.org/body/exercise/delayed-onset-muscle-soreness-muscle-pain