When I saw the prices of crypto currencies there is almost every coin's price fell upto 20%.Do you think this is just happening due to South Korea's ban over crypto currencies or there is other reasons for that.
I hope the condition will be back normal soon but I am worried a lot.

There is a lot of hype around Korea and China which certainly affects the price falls. FUD and bad news lead to sales. After correction, everything should return to normal and the price will increase.