Hi.. Thanks for the query.. It looks like you have inflammation inside mouth causing Stomatitis and it is causing inflammation and soreness inside mouth.. Congestion in left ear can be due to excessive wax build up or there can be fluid behind the eardrum.. Cough can be due to lung Infection or bronchitis.. So you should consult an Emergency room and get evaluated and a thorough examination and investigation like x-ray and complete blood profile can help in diagnosis and treatment can be done once the cause is ruled out.. For now use decongestant nasal spray like Xylometazoline or Oxymetazoline. Do steam inhalation.. Take cough suppressant containing Dextromethorphan.. For soreness and inflammation in mouth you can gargle with numbing mouth wash containing Lignocaine. You should start taking Vitamin B complex supplement.. Do warm saline gargles.. Avoid spicy and sour foods.. Hope this helps.. Regards..