What Causes Severe Pain On The Right Side Of The Back?

i recently noticed a sharp pain on the right side of my back not in the middle more to the side of my middle of my back its a quick sharp tighting Im thinkingg like a spasam but when it does this it its a sharp pain stops me in my tracks lasts a few seconds but almost breath taking in those seconds. Its happening more often then when it started but it seems to be after a days work when it starts and heat and cold ease up the the tightness I feel after these happen. I feel a knot like ball and I can tell you right where it does it everytime but after Ive relaxed or worked it out with a heat vibration or a heating pad it releases that ball like feeling .