It looks like  you are filing your tax for the first time-first year in US. There are few things you need to understand:

1. Amount of Tax you need to pay is subject your TOTAL ANNUAL INCOME.

2. Your TAX WITHELD wrt your income( which you think in your word "I paid all the taxes") may still be insufficient, in that case you will have to pay extra amount -which is indicated in your CINTAX. So you should pay the remaining tax.

REMEMBER- IT IS YOU ARE FILING TAX RETURN-NOT REFUND, meaning if your tax withheld is higher than it is supposed to be wrt your annual income, you will get refund, else, you have to pay!

hope it helps!