The pain you describe could likely be completely unrelated to your past smoking - but scream of arthritis. Yes, arthritis, The waning of the pain after exercise also points to that condition. Did you injure that shoulder when you were young...and how old are you? You may not even remember an injury - or that may not be an issue, as arthritis hits some of us - MOST of us - out of the blue.
As far as your elevated WBC, that indicates you're fighting off an infection. Flu season is here - and are your kids in school?? I'd hit Vitamin C with a vengeance as well as Echinacea.
Please don't jump to conclusions as far as having cancer - please. Although the resources we have for health issues are incredible online, it's no secret that symptoms can and are the same for many conditions. As a Parent, it's commendable you want to be healthy for your little ones! Please don't teach them to worry until there's an identified problem - and then, simply handle it with a grin. I know all too well that life is what happens when we make other plans, and planning or worry over an illness that's unidentified is simply not a good thing. Not for you - not for your little ones. They can sense worry...
Remember, you are way early in whatever you have. Claim it is a minor thing. Claim that! Keep exercising and force it into the background until and unless it becomes a quality of function issue. Positivity makes a huge difference in the quality of anyone's life.
Be well,
Dix
Have you been lifting or carrying anything heavy?
It may be an arthritic problem and you may benefit from a massage and gentle exercise so that it does not stiffen up.
A raise in the white blood cells usually indicates that your body is fighting an infection. Has the doctor given you any indication what to do about that and whether you need any follow up checks?
Well, you may not have anything. It sounds like you are over worrying. But since you are worried it can't hurt to get a CT scan or an MRI. Do you have any other symptoms such as fatigue, weight loss? It is up to you to wait and see if the pain isn't a strain and will go away or not. How high was the WBC count?