The side screw doesn't come all the way out. It is pinned so it won't do so, and get lost. It only comes out about one half inch. At that point you pull straight back on the stock while holding the front part of the rifle.
If it doesn't come out, I suspect rust is involved. If so I would use penetrating oil dripped into the action while it is pulled back so the oil can settle into the bottom of the action (rifle held level- trigger guard down).
Try to take the rear stock off the action by removing the large screw at the rear of the action. This is simple to do and will prevent the oil from soaking into the wood.
Let the oil soak in the action for a day or two and tap on the lower tang with a piece of oak wood or plastic mallet to help the oil soak in. After two days try tapping on the front of the trigger guard- lightly! Many light taps are better than a few hard ones and will save the action from being damaged.
Keep soaking and tapping and it should come.
Good Luck,
williek