Hi. I Believe That I Inhaled A Grain Of Cooked

Hi. I believe that I inhaled a grain of cooked rice last night while I was eating and talking at same time. I tried to cough it out but not sure it came out. Since yesterday I have been coughing whitish mucus and not feeling confortable .. after a couple of hours from the incident I tried to do some coughing up exercises that watched on utube to help with getting it out but not sure as I was checking the mucus I am coughing and nothing there. Today I woke up and my throat feeling very sore from the exercise and I now afternoon kind of feeling short of breath a little and tired and I am not sure whether its because of the grain could gone into my lungs or because I am starting to panic. Please advice. Thank you