[Gisèle]

Since about July, I've had this sharp, piercing, stabbing pain on my left side by my heart, which can happen anytime, but is mostly when laying down and when I sit up it lessens up. It is on and off, I don't have it all the time, but it seems like I get it at least once a day. It also lasts a while, sometimes up to 20 minutes. I ignored it thinking it was just heartburn or something simple like that. Also since July, I've had shortness of breath, like it's hard to take a deep breath, and that's mostly when I am laying down. Since July, I have noticed both of these problems more often. I ended up getting a EKG echocardiogram, and chest xray recently, which all showed normal results.
My family doctor thought pericarditis. Could it still be pericarditis considering the three tests came back normal? What other tests can be done to rule out pericarditis?
Also, if it's not pericarditis, what are some other possibiltes that I can ask my doctor to check for?
If this applies to this chest pain I am currently thought to have an autoimmune problem, possibly SLE, but the ANA came back negative.