Miner modify pending block (not yet on chain) and successfully solve the PoW For example, I pay a cup of coffee with bitcoin, and later remove that transaction from the pending block that is not yet on chain. After 10 mins, I successfully and luckily solve the PoW problem, and broadcast the modified block to everyone as well as append it to the blockchain.

Is the scenario above possible? If it is, how is it prevented?
It is perfectly possible, and it is why it is discouraged to take irreversible action based on transactions that are unconfirmed (=not in a block yet).

However, the transaction is not invalidated just because it is reversed. Another miner can still include it at a later time, unless you issue a conflicting transaction  (=double spend) with a higher fee.