Mac, the lumber used in a house
is straight as considered reasonable to work with. Anything less, it goes back for exchange. Using lumber to frame is suppose to be flexible enough and with enough moisture content to work with. You just don't want any wane, warp, or
too many knots. Once the lumber is secured in a frame, then the frame itself will keep it straight once the covering is secured. That is why I said to make sure it is square, plumb, and secured well. If you want something perfect and have the money, by furniture or cabinet grade.
I'm not sure of the tone in this remark, Squid, but I assure you that I have plenty of "real-world" experience. I am 63 years old and have worked with lumber for my own projects that have included everything from cabinets, furniture, and sundecks to room additions, not to mention a couple of years house framing for my carpenter FIL. I even worked in a high tech sawmill for several years that made dimensional 2x lumber for the housing industry. Now, relative to the topic, I have a 24x40 garage size layout that has varying temperatures and humidity in both summer and winter. Surprise: it's pine and hasn't warped/distorted one little bit, but you see, I built it right!
Actually, most dimensional lumber used in houses is not pine. If you look at a stud, it will say SPF, which means spruce/pine/fir. It could be black spruce, jack pine, or douglas fir. All woods with similar properties, but not likely white pine (or at least not very knot-free white pine) since white pine is prized for furniture, trim and other finished products.
You sir, have your facts wrong. KENW is correct and offers excellent advise. Spruce is probably the worst wood I have ever worked with, but fir is usually a pretty good option.