Uncomfortable sex

I just recently started having sex with my bf (using condoms) but I have found it to be uncomfortable to downright painful. Using lube helps a tiny bit and briefly but it gets painful pretty quick after. He says it's because I'm really tight and it will take some time before I'll really like it but to be honest I'm getting absolutely nothing out of it. I'm lucky if it's just uncomfortable. Anybody know why I'm so tight or how it can be more pleasurable for me?