I Had 4 Stents Put In 2 N Half Months

I had 4 stents put in 2 n half months ago , I take nitro spray , when ever I have some discomort in my chest , like a burning pain , or soreness , how often should I take the spray they told me after 3 sprays , if the pain should not go away , to go to the hosptial , it does go away , but some time s this happens a couple of time in a day