HELP! Banks don't approve my application.?

Hi. I've been here in US legally for 5 months when I entered as a fiancee visa. Now I applied for my social security and got a number. My husband and I applied for a joint account in Chase bank and they didn't approved it. Months later, we went to Costco to get an Amex card and he requested Costco representative if they can put my name under his account. So they requested my SSN. Week later, I got a letter from them saying they can't approve our application because of my SSN. We don't even know why. Since I am new here, I never had any credit history. We have no idea why they can't approve it. I have my EAD on hand good for one year and my permanent residency is still on decision.. Please help. Thank you so much!