Mystery Ailment

Apparently I've been too healthy for too long because now I get to figure out the newest mystery health problem. I suppose the fact that I go for long-ish periods of time being healthy I shouldn't complain. I also have not had anything fatal so that's a plus.
I have been trying to train for a 5K for this Saturday since January. Previous posts have established I am not a runner. I am a wanna-be runner though so training has taken much time and practice. My partner and I have been upping our training and going to the gym more frequently. We ran on the treadmill on Monday, lifted weights on Tuesday, and ran again on Wednesday. I ran hard. It felt good! I went about 3.2 miles and pushed myself. I've mostly been sticking to the elliptical because the treadmill always makes my shin splints flair up. Which is really weird because running outside doesn't do that. I know. Weird.
Shortly before lunch on Wednesday my chest started to hurt a little. I didn't really notice much. Then I fed the boys and a little while later it was time to lay down for naps. I like to lay in the room with them. This accomplishes two goals. They actually stay laying down and go to sleep and I get to rest and even a cat nap. As I lay down on Wednesday my chest really started to have sharp pains. Not heart attack type pains. A sharp stabbing pain under my right breast on the inside of my ribs. The longer I laid there the worse it got. I actually fell asleep from being so tired though and the pain woke me back up. The boys were asleep by then so I snuck out. The rest of the day it was still there. I can't inhale deeply or it stabs painfully. It doesn't hurt when I lay on my left. Only my right. I can always feel it there but really bad laying on my right and breathing deep. Which means any time I exert myself, like going up or down the stairs and breathe. Or running. Or carrying a load of laundry up the stairs. Dumb. Dumb, dumb, dumb!!!
I have a doctor's appointment tomorrow at 2:00. Hopefully the doctor will say it's fine. Take Ibuprofen and I can still run my race on Saturday morning. That may be wishful thinking.
From my professional research done on my WebMD app on my phone I could have a couple of different things. Pleurisy, pneumonia, or this one word that starts with a C that I cant pronounce much less spell...... Pleurisy is when the fluid in between your ribs and lungs get a hole in it and the lung and rib directly rub against each other. Chad has had it a couple of times. It hurts. A lot. Then the weird C word one is the one I think I have. It's when your joint between your rib and the sternum where they connect gets inflamed and sore. The reason I think it's that is the symptoms fit the best. If you press near the stabbing pain it gets worse. With pleurisy it would relieve some pain. Also, deep breathes make it worse. The location fits. But I'm hoping it is not that because the only thing I can do is REST. Any of you moms out there understand instantly how impossible that task is. Pray for me. Oi.