I was told pine is the way to go for portions of my project but I'm also told framing pine is not the way to go because it's not square and is not dried. Can I just go to a big box store and get pine that's good for projects? What specifically should I be looking/asking for?
Yes, you can use Pine for framing. There are many kinds of pine, 1) Lodgepole Pine, 2) Ponderosa Pine, 3) Idaho White Pine. Which is available, will depend on where you are located.
However, Pine is a “soft” wood. That’s why you’re hearing from folks talking about different species.
So, depending on what you are doing, I’d recommend: 1) for general framing, Pine is fine. 2) For large structural jobs we usually use a denser wood like Fir, Spruce, etc. 3) for wood that’s exposed to the weather, we use Cedar, Redwood, but they are a “soft” wood too. 4) for trim, Pine is fine and is usually very economical. 5) for boards to walk on, we use oak, alder.
To get wood that will hold its shape best, I’d use wood that has been “dried”. They do that two ways: 1) kiln dried, and 2) air dried. “Green” lumber (lumber freshly cut from a tree) will twist and warp as it dries out. Lumber is graded on its “moisture content”. (The weight of the water in wood.) Green lumber is usually in the 22%-19% moisture content range. If it’s air dried it’s in the 15%-12% range. Kiln dried is in the 12%-9% for framing and 8%-5% for trim, furniture, etc. Of course the cost goes up the more it’s dried and it all varies based on the relative humidity where you live. When they dry it, they bind the stacks of lumber together so they don’t twist so much. Sometimes better than others.
So, to answer your question, if you are framing, I’d use the driest, straightest, Pine available without large knots, etc. Usually, the lumberyards will let you pick through the stack if you don’t need many boards. If you’re building a fence or an outdoor trellis, I’d use cedar or redwood. (Pine will rot very quickly outdoors.)