What Can Cause Strong Pulsating Feel In Abdominal Area?

Female, 25 years of age. Normally text-book good blood pressure. 64kg and 168cm. Have been sick with flu like symptoms for about 4 weeks. Tonsils were inflamed. Went to Dr last week and he said they had gone down and could not hear any crackles or abnormal breath sounds. He said it was probably the tail end of an infection and that it should clear up. Cough has got worse today so went to bed in afternoon. Had stabbing like pain in chest and could feel my pulse very well, almost like it was beating harder. Pain is better when I sit up or get up, worse when lying down. Just noticed that I have a very strong abdominal pulse (to the point where if I put something on my stomach it elevates it. This was not present earlier in the day, as I had been a model for a teaching class and had an extensive abdominal assessment by 3 people. Normally take SSRI, dopamine medication and just started contraceptive pill a couple of days ago.