tough question on resume, need advice

I was wondering that if HR will check a job candidate\'s previous job title or not? Assume it might happen before or after an offer was given.the different is a Senior word.
My case is a little unique, my previous job was not a senior level but I did a lot senior stuff. However for a couple of reasons, I did not get my promotion which was subdue and I list patience and move on. Now I really need that title to get me back in the industry, market is very tough and I have wife and kids to support.

Will these HR people submit background check to a third party? How detail they verify employment history? specifically if it include job title.
Please don\'t bash me, I have to survive.
Please share your thought, whether if you are in HR or are hiring manager.

Thanks a million!