Can an enlarged prostate cause constipation?!

Can an enlarged prostate cause constipation?

I have been dealing with constipation for a really long time (about a year and a half), and I've tried everything to make it go away (including lexatives), but nothing has worked. The stool itself isn't rock hard, but the main problem is that it takes a lot of straining for it to come out. In addition, I sometimes experience pain after ejaculation, and also I have noticed that some times after I urinate I have a feeling like I'm not completely empty, so I have to urinate again after a couple of hours. This has been going on for a long time as well. So I was wondering, if theres a link between these two. Keep in mind that I'm only 21 years old.

I suppose it could, if it's like soccer ball size.