Gym buffs will be familiar with post-exercise soreness, which is formally known as delayed onset muscle soreness or "muscle fever." The good news is that it goes away after awhile, and there are a couple of things you can try to ease the pain, starting with:
Work Out the Knots In Your Muscles

If you feel up to it, jump straight into some light exercise like walking or swimming. By keeping your muscles in motion, it may bring you some relief. Avoid heavy exercise until your damaged muscles are repaired (takes around 72 hours). You can also try a little massage therapy to help soothe that muscle tightness.

What to Eat When Your Muscles Are Sore

Omega-3: Sore muscles can sometimes by a sign of either dehydration, lack of sodium, protein, electrolytes, or vitamins. Omega-3 fatty acids have been shown to reduce inflammation, and delayed onset muscle soreness is basically inflammation. A study published in the Journal of Sports Science and Medicine recommends fish oil omega-3 supplements or eating foods rich in those fatty acids such as salmon, avocados, and almonds.

Water: Drink lots of water to stay hydrated. If you're looking for an alternative to sports drinks, try coconut water as it's very hydrating and a natural source of electrolytes.

Get Enough Shut-eye

When you're body gets a beating, the best way to recover is to just get enough rest. Your body releases growth hormone during sleep, which helps repair any damage that has been done to your muscles during intense workouts. Taking a twenty to sixty minute nap once a day is also a great way to see faster results.

Contrast Baths or Ice & Heat Packs

Contrast bath involves submerging yourself in hot water for one minute then ice cold water for a minute and repeat for up to ten minutes in the shower. The cold is a natural analgesic that soothes the muscles and the warmth then relaxes them. You can also use ice and heat packs instead of water to achieve the same results.
And always remember, the "no pain no gain" mantra is a big misconception. You absolutely don't need to feel sore the next day to have had a good workout.