Are ballistic missiles guided missiles

Yes, although not in the same sense as, say, an air-to-air missile. They're programmed prior to launch.

Technically, a ballistic missile is, by definition, unguided, as it follows a trajectory dictated by pure physics (hence, the name "ballistic").

However, the vast majority of modern ballistic missiles are equipped with a warhead which does have a guidance package. So, the ballistic missile is launched, and follows a predictable flightpath. At some point, the warhead deploys, and then, the warhead can steer itself onto target. In some cases, (such as nuclear ICBMs), the warhead is actual a subassembly (called a "bus") which contains multiple actual warheads, and the bus itself is guided. In other cases, the warhead is a single package with guidance and steering integrated into it. The key here is that the missile itself is unguided, and follows a standard path, while the warhead package may or may not contain guidance.