Possibly Enlarged Prostate?

Recently I've been having difficulty getting urine stream started. Takes a couple of seconds but it eventually all comes out, and when it does come out doesn't even really seem like it was full. But before that started I was having this sharp sorta stabbing pain up my butt usually happening at night when my bladder got empty. Recently that pain hasn't been occurring really at all lately, but the only feeling I'm getting now is a pressure up there. Like there's something up there but can't get it out. Can't tell if that's constipation or what. Anyway this seemed to have all started after I had lost 40 lbs by dieting and lots of exercise, mostly elliptical cardio. Could that maybe have agitated prostate and cause it to enlarge? I dunno how it works but I thought I'd add that. Here're a couple of other things I might add to narrow down any issues:

No bowel issues/no blood
No ejaculation or erection issues
No burning pain or anything like that during urination

So does anyone have any input as to what it could be? If it's enlarged prostate will this go away on it's own or should I get medication, or some other medical help? I just feel hesitant to come forward to a doctor with this humiliating problem but if this is going to get worse I would like to fix it now. Thanks for any info