This is a small stone. It will pain if it blocks a small urine channel. It will pass through bigger urine channels. If it blocks any channel, it can pain a lot. Usually stone less than 5mm have the capacity to pass out of the urinary system. Slightly larger stones may take time or may not be able to pass out. Also, stones present before the the bladder (in kidney and in promimal ureter) has less chance of expulsion than stones present in urethra or at the junction of bladder and urethra. Medications, such as a combination of tamsulosin and a corticosteroid are often given to help expel the stone. Along with it patient needs to take plenty of fluids, cranberry juice, apple cider etc. If stone does not pass out, it can be broken by lithotripsy and this then flushes out of system with urine. Do discuss this with your doctor. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.