Wall Cracks Around Windows and Door Frames

[Abigail C Simpson]

I purchased my home about 3 years ago. It was built in 1930 but was flipped, so new walls/paint/etc.  Over the three years, several cracks have appeared around window and door frames and around the stairs. I attached a photo of one of the cracks. How bad is this? We had a structural engineer come when we first were in the process of purchasing to check out our crooked floor but they haven't returned since the cracks appeared. 

Thank you!