First some background:
Our home is a 2 story detached. On the main floor it is entirely open concept, with a ~14' drywalled horizontal support beam separating the kitchen from the living room area. This "beam" (i call it that because i don't know exactly what is behind the drywall yet) comes down from the ceiling about 1.5 feet and has trim on it etc... The home is about 7 years old. We were the 2nd owners of the home (it's a builder home). We have 9' tall ceilings on the main floor. Our master bedroom & bathroom are directly above this area. The bathroom has a soaker tub and a separate tile shower. We have had no issues with windows or doors not opening/closing properly.
When we purchased the house, we noticed in the upstairs master bedroom (which is directly above the kitchen) that the floor was pretty squeaky when walking on it. We had the seller 'fix' it but whatever they did, didn't last very long as the squeaking returned shortly after we moved in. That was about 5 years ago.
Over the years we had noticed a couple straight almost hairline vertical cracks in the drywall surrounding the support beam on the main floor. Definitely seemed like tearing of the drywall tape. Last month we had our basement finished and one of the contractors pointed out that there is a bit of a sag in support beam that we never noticed until now. They got out a laser level & confirmed the beam is sagging about 5/8" in the middle of the 14 foot span it is supporting and there is some slight bowing in the ceiling near the beam. There are no cracks in the actual ceiling yet, just the beam. We have not noticed any water damage in the ceiling.
We just patched the cracks around the beam and have started measuring the distance from the middle of the beam to the floor on a monthly basis and are watching to see if the cracks come back.
Part of me wants to open the ceiling and get a home inspector in here to evaluate the cause but i don't want to open the drywall unnecessarily either.
We are kind of freaking out about it, now every little crack we find in the house makes us wonder if it's related...
We are not particularly handy people and are unsure how to approach this problem, so any advice would be most appreciated.