Suggest Treatment For A Rash Appearing On The Stomach

Hi I have had a rash of red pinprick spots on my stomach for the last 2 1/2 weeks. I haven't changed my diet or my clothes. I have changed my shower gel since the rash and that hasn't made a difference. I also feel dizzy, very lethargic, drowsy and i have a headache. A couple of days ago I also had a sore throat which lasted for about 48 hours. Since today I have also started to get a pain just below my ribs- it hurts to cough and to kneel down. What do you think this could be?