I can relate!!!
In January, I strained muscles in my back, shoulders, neck & chest carrying around my then 20 lb. 1 1/2 year old while we were all sick with nasty colds. I started getting freaked out when the chest pains started. I knew it was muscle strain, but I saw a doctor just in case. She assured me it was. About a week later, it was still freaking me out, so I saw another doctor. Seeing how upset I was, she had them do a full cardiac workup (chest x-ray, EKG, bloodwork). Everything came back perfect; they said it was muscle-related. I started stretching & trying to relax a bit (meditation isn't really something I can do well with 2 little kids & a dog always bothering me!). The muscles in my chest, neck & shoulders loosened up, and my back was on & off, so it was improvement.
Then in April, my right foot fell asleep & it would do that on & off for a week. When that spread up my leg, it freaked me out. My first thought was that I had a pinched nerve, but of course, I thought it could be a bloodclot (even though I had no other symptoms of one). So a nurse that spoke with had me go to the ER. Pinched sciatic nerve. More stretching & exercises to work on that.
The week before Easter, I started feeling "off". Kind of lightheaded or dizzy, but not really. Looking online, I read up on derealization, which described exactly how I was feeling. On Easter, my ears wouldn't pop & were like that for 2 days before draining for a few days. I assume it was my seasonal allergies starting, even though that's not a symptom I normally have. But apparently that was the week a lot of people's allergies kicked in. Since then, I've had more normal symptoms, like red, irritated eyes in the morning & a stuffy, runny nose.
Last week I had a tender spot on my lower right abdomen, which I assumed was from one of my kids doing something to me. I was ignoring it until I had sudden sharp pains on my lower right side. It happened several times while I was cleaning, so I sat down & it happened a few more times. Long story short, went to the doctor & she said it was more than likely muscle-related. (She asked a ton of questions & did a good physical exam of the area. I didn't have any of the symptoms she was looking for.) And the spot I figured was something my kids did to me eventually produced a nice big bruise.
On Saturday, my back muscles tensed up nicely, making me miserable. I'm assuming the stress caused it, since I had been fine for a over a week. I had some nausea on & off, which I was told was probably from the muscles spasming. (This has happened a few times when my back was REALLY bad, otherwise I don't have nausea or else I'd be concerned over that, too!) Today my back seems to be loosening up, but I'm having the "off" feeling again. I'm starting to notice that I feel that way when I have a headache, which is usually being caused by tight neck or shoulder muscles. Ugh. It really never ends. I was normal before all this began a few months ago. I've worried about so many things being wrong with me. It's like I can't except that my problem is probably that my chronic stress is causing muscle tightness. I have a lot going on over the next couple of months, so I'm hoping that will distract me without causing further stress. I'm also having my first professional massage on Friday, which I'm hoping will help.
Sorry for a long response...but I definitely know what you're going through!!!