Mazda Protege 2003 It is a jittery ride, quite hard and unpleasant at times

All equipment is original, with the exception of normal wear and tear items. Would different shocks, tires, etc., make driving less like riding a pogo stick? bounces over railroad tracks, but is a rough ride when going over any obstacle beyond a perfectly smooth surface. It has ALWAYS been this way, not something which has developed over time. I realize it is a small car and won't drive like a big Buick, but, geeze.