I reinstalled metamask after formating my pc but, no tokens where available there can somebody please tell me the reason and solution as well?
Your tokens doesn't store inside of MetaMask. So, you can add them again by clicking to "Tokens" button and pasting there address of token. I wish it will help you.
P.S. It's a quick answer, let me know if you need screenshots how to do it.
In order to "get your tokens back" you should unlock Metamask using the 12 word mnemonic you had previously used, which holds your private and public keys. Open Metamask and choose "restore from see phrase".
If you reinstalled Chrome and Metamask you'll possibly also have to re-add the tokens again by choosing Add Token -> and entering the corresponding token address, as Metamask doesn't automatically retrieve the tokens you own.
I can confirm that you will need to re-add your tokens once you restore your account form your 12 word seed phrase.