Change name?

I have two social security cards, they have the same number but different names. The first card has my first, middle and last name. The second card has only my middle name and las name. Anyway, all my life I have gone by middle name no one knows me by my first name, however on all my legal documents I have always used my first name (like income tax forms, other jobs, drivers license. I am about to graduate college and will be looking for a job. All my references know me by my middle name, so when I go apply for a job should I just use the SS card that has my middle and last name, but what if the employer does a background check what will it show. I dont even know why I have two SS cards thats just what my mom got. I hope it makes sense. Sometimes some job applications have a space where you can put other names you have been known by what if I put my full name or does that look suspicious? Do you guys know how I can drop my first name legally and does it cost money?Change name?Get this sorted out legally, without further complications, by hiring or taking help of a good, dependable lawyer. You may have one lawyer, in your own family. Check it out first, with your family seniors who are pragmatic and wise.
Change name?
you would have to go to court to change your name legally .it would probally cost a couple of hundred