Is a chocolate considered frozen if it is on the shelf in a store still solid?
Technically, yes. Solids are the state of matter when it's molecules have little kinetic motion, arranged in a latice-work of orderly arrangement. This molecular arrangement is what makes solids "solid". Liquids have less orderly arrangement, and gases have no orderly arrangement at all. Gases may be converted into liquids by condensing their molecules, and liquids may be converted into solids by freezing their molecules. So chocolate is technically "frozen" while it's molecules are in a solid state of matter.
Do not confuse freezing with temperature, however. If you measure the temperature of the "solid" chocolate, you will find it is fairly close to the room temperature of the store, probably somewhere around 72 to 76 degrees Fahrenheit. Not hardly what we would call a freezing temperature, typically associated with the freezing point of water, which is 32 degrees Fahrenheit.