What do these weird symptoms--fatigue, malaise, widespread pain, lack of appetite, chest pain, shortness of breath, rashes, weakness--mean?

I'm not a doctor, just to make it clear. But I had a heart attack before and I had experienced all the symptoms you're saying here. Just like you, I live a healthy lifestyle- no smoking, gym, eating healthy. But I still had an attack. Pain that usually start at the lower abdomen then radiating to upper left breast to left shoulder is a sure sign of an impending heart attack. I would suggest you consult a heart specialist and ask for an Angiogram, this is the best way to see if there's a blockage in your heart. Second opinion wouldn't hurt you.

Your fatigue problem could be related to most of your other problems.

Fatigue is often due to an unhealthy lifestyle.

Fatigue often triggers off further problems such as headaches, migraines, dizziness, lightheadedness, shakiness and nausea.

To combat fatigue perhaps the energy vitamin B12 can help or a vitamin B complex. Coenzyme Q10 can also help to boost your energy level as in a web search for "coenzyme q10 for energy". The super food Spirulina is another good energy booster.

One of the most common fatigue causes is anxiety which is a state of fear of real or imagined danger, which is manifested as increased heart rate, trembling, panic, weakness, extreme fatigue and stomach or intestinal discomfort.

Besides anxiety there are many other common fatigue causes such as insufficient sleep, too much sleep, under eating, thyroid problems or other illnesses (such as anemia, mononucleosis, CFS, glandular fever and many others), side effects from medication, dehydration, overexertion, an unhealthy diet and other causes as discussed in a web search for "common fatigue causes".

ill label some things i think it could be,

1. Anxiety, we dont like to hear that, but stress can make us feel stuff that isnt pleasent.

2. Limes Disease, if you live somewhere with woods, definetly get checked! Ask them to do bloodwork for limes if so.

3. Could be an illergic reaction to a medicine your taking.