- Hi Karla here, woke up Sunday morning with excruciating pain in my left arm could not believe what had just happened , it was 3.30 am in the morning , thought maybe it was a sign of a stroke, me chest felt fine , my breathing was ok , so I did not panic , the pain was so bad ,I took a inflammatory, 2 panadine forte waited an hour then went back to bed, got up at 9am still felt very sore I felt tired and quite sick in the tummy. Monday morning felt a little better but arm still very sore. around 4pm Monday I noticed a red swelling about 6inches by 6 inches on my left upper arm mussel,only then did I think I was bitten by a spider. I don't know what spider it was ,I took myself to the doctor he said probably a red back spider, my arm is still very sore but getting better, does anyone know how long it could be sore for I forgot to ask the doctor that question. thanks if anyone know the answer to that question , regards Karla..