Pericardial Effusion

Hi all--if you can stand to read this brief history, I'd appreciate any firsthand experience or first-rate info you can offer:

In November 2009, I went to the ER late at night for a 104 degree (and climbing) fever.  They were unable to tell me what was wrong, only that it was a viral infection.  I went home with a diagnosis of "viral pharyngitis," which made no mention of sores inside my mouth and on my lips.  They noted my high pulse, but attributed it only to fever.  I took the usual ibuprofen-acetaminophen combo until the fever went away.  The sores went away within a week.  The staff at the ER referred to my blood work as "very good."

Then, in December 2009, I went to the ER a second time with a pulse of 120, but no other symptoms.  They did an echocardiogram and found I had a pericardial effusion.  I was told to take ibuprofen and that it would go away on its own in a few weeks.  My blood work was again pronounced "very good."

It's now nearing March 2010 and though for a while between January and February my pulse improved, it is now getting worse and on top of it, I have chest discomfort and slight shortness of breath.  I am concerned the problem is getting worse, and looking for answers as to what could be wrong.

Previously, I ran twice weekly.  Only recently I have tried running again, but my pulse goes above 160 if I run 6 mph for 2.5 minutes, which is considerably higher than usual.  For example, in October 2009, I ran 6 mph for 2.5 minutes and my pulse barely broke 130.

In particular, what could cause such a problem?  I was initially afraid I might have HIV; however, I do not engage in risky behavior and myself and my partner have both tested HIV negative in October and January.
- Could a coxsackie virus have caused the initial infection and the effusion?
- Could HSV-1 have been the culprit?  I recently discovered that my partner's roommate has HSV-1, because she uses a topical ointment for cold sores.

Could a virus cause a prolonged effusion such as I have?  If not, what could?

If I was administered minocycline (orally) 8 years ago, would this have any effect on my pericardium that would make me more vulnerable to a pericardial effusion?

If this persists, can it have long-term effects on my heart (e.g. thicken the muscle or anything like that)?

And lastly, of course--  ADVICE?  Anything OTC I can take before I decide to make an appointment to get another echo and see what's what, at the expense of time and money I don't have?