Carrying a 4" L-frame revolver can be a bit of a challenge. Concealment will require some thought. Comfort will require some thought.

My first recommendation would be a good pancake-style holster, worn strong-side slightly behind the point of the hip (roughly 4:00 position). The pancake design tends to conceal the profile of the handgun better than most other styles, while the fore-and-aft belt attachment points spread the weight over a larger area of the belt.

My second recommendation is to make sure you have a good solid gun belt to anchor the holstered handgun firmly in place. No holster can perform to optimum levels unless provided with a solid foundation on the body. Your 4" 586 will weigh in at about 2.5 lbs. loaded, so don't expect a department store belt to do the job.