What Are The Side Effects Of Instaflex?

I have been taking Instaflex since Saturday morning. I am noticing that in the afternoon I experience and unsettled stomach. Is this normal? Do I take all 3 pills at one time or one 3 times a day? I am a 70 yr. old woman with authritis in my knees, hands and shoulder. One knee has been replaced. I don t quite know what else to tell you.