Lower back pain when moving certain ways

Since sunday I have been getting pain in my lower right back, it's definetely inside and not anything on skin/bruises etc. Though it feels like lower back pain, when I tap/hit my back lightly it feels more towards the middle right.

I drank quite a bit of alchohol and smoked on the weekend, I dont usually smoke but drink every couple of weeks.

It's not a pain that comes and go, where as it's more where I move around, like run down the stairs, or bend over to pick up something. If I sit still I dont usually feel any pains at all.

I've never had any kidney problems, but have drank a lot over the years, i'm 21 years old fairly healthy male.

Also I should mention I started doing weights again last week, but I dont think it would make my lower right back sore. My biceps and chest were really sore for a few days (As they get after working out)

Is this anything to worry about?