Without any further information, if you feel this is a true emergency, the short answer for sure is YES
If the problem has come on suddenly or you have fallen or got knocked, then yes you would be advised to go the hospital to the emergency room straight away for an evaluation.
If you have been having this as an ongoing problem (you do not say which side you are having the pain in) and the side pain has been there for some time too, then make a routine appointment to see your doctor as soon as you can.
For emergency treatment with relation to the side pain, this depends what type of pain you are experiencing and where on the body it is and whether this came on suddenly or progressively got much worse and whether the temperature is elevated and other symptoms present.
As you are 56, it is likely that you are suffering from an acute phase of osteoarthric or other arthritic problems. Take your prescribed pain relief for this and rest in bed with plenty of warm fluids.
Best wishes.
I would definitely suggest a trip to the ER if your pain is severe. hope you feel better