Gear up boys and girls: Time to do some MATH.
I have no way of knowing what sort of tonnage your spacecraft will be displacing, but just for kicks let's assume you somehow got an Iowa-class Battleship into orbit and are worried her main cannons are going to cause a recoil problem when you fire on the enemy.
* The ship will weigh approx. 58,000 Tons, or from here forward a "Fuckton." This equates to about 52,000,000 kg of mass.
* The primary battery on an Iowa-class is its nine 16"/50 Mark 7 guns. These weapons can fire a wide variety of payloads, but their most potent non-nuclear is the Mark 8 Superheavy Shell, weighing 2700 lb with a muzzle velocity of 2500 ft/s.
* Now, momentum is computed based on mass x velocity, so a quick multiplication (after converting to metric; we're not barbarians afterall) yields a change in momentum of 925,830 Newton-seconds (a unit we don't really need to care about right now). This was from a single shot. 898
A full broadside of all nine cannons would produce a change of 8,332,470 Newton-seconds. That sure sounds like a lot...
* ...But not when compared to the Fuckton of mass onboard the Battleship. A division of the change in momentum by the mass of the ship will give us a hypothetical change in velocity after the broadside, which comes out to be about 0.16 m/s, which is about four orders of magnitude beneath orbital velocities.
To keep a typical spacecraft in low orbit requires periodic stationkeeping to counteract atmospheric drag. This is usually on the order of a few mm/s. Our full broadside would require stationkeeping efforts of hundreds of mm/s, but based on the assumption we managed to get something as massive as a battleship into orbit, I would assume a few hundred mm/s is well within the delta-v budget of the ship.
Of course, your ships could be much smaller and fire much more energetic projectiles, and in that regard you may encounter a problem, but remember that orbital speeds are in the thousands of meters per second, and that a ship with the energy to fire highly energetic weapons will likely have equally energetic thrusters.
Plus you could always use lasers. 898