this can occurs due to weather changes and temperature variations or simple cold and rarely infection. kindly give nasal saline drops (nasoclear /nasivion s)every three hourly and since it is a salt water/saline water it does not have any side effects and can be given again and again for nasal blockage and respiratory cough. it will dissolve mucus in nose and throat. for fever and pain give paracetamol. anti-cold medicines at this age have got side effects so can be given only after medical consultation. try to prevent temperature variations around the child and you can also give indirect steam inhalation and if there is no improvement in 2 or 3 days then meet your doctor 

Nasal saline drops

Hello ! Syp maxtra 2 ml thrice daily for 3 days Syp kufril Ls -2 ml thrice daily for 5 days Maintain hydration Avoid banana Avoid cool drinks, ice creams

Nasoclear nasal spray 4 to 6 times a day For 2 days Continue breastfeeding. If anyone is having viral, Then wear mask, hand washing and social distancing