Brief Answer:
Regarding anxiety:

Detailed Answer:
Hello and welcome.

I think it would be a good idea to see your doctor with help managing the stress and panic attacks. But first about the other symptoms.

The good news is that chest pain from cardiac causes is not usually sharp, and can get worse with exercise, never better with exercise. So the cause is most likely musculoskeletal (such as from a strain). Other possible causes of the chest pains are acid reflux (you might notice more of it after a large or spicy meal or acidic food), or anxiety. Certain respiratory problems can cause chest pain, but are usually accompanied by coughing, difficulty breathing, and sometimes fever.

The appetite changes and irregular breathing can go with anxiety and panic attacks but are associated with many different things so are nonspecific symptoms in this context.

So I think it would be a good idea to go in to a doctor and have an exam to make sure that there isn't any underlying medical problem going on, as it is not a good idea for us (doctors) to just chalk things up to anxiety before making sure the medical possibilities mentioned above are not an issue. Your doctor should listen to your heart, lungs, check your thryoid gland and abdomen. TSH test for thyroid function should be drawn (a blood test).

Now about stress and panic attacks. I've had panic attacks and know they are miserable. If you have been having these for a while and it seems to be an ongoing thing, an SSRI medication such as Lexapro (escitalopram) can treat the anxiety/panic long term. But it takes a couple weeks to start working. In the meantime, you may benefit from a benzodiazepine such as lorazepam. These work immediately but can be quite sedating. Be sure you are getting enough B vitamins too.

I also recommend seeing a psychologist for talking about any issues that he/she can help you work out.

Exercise is great for dealing with stress and anxiety so keep that up.

Also consider learning mindful breathing techniques. Four by four breathing is an easy one to learn. Find a comfortable position seated or lying down. Breath in counting to 4, breath out counting to 4, focusing on the breaths. Repeat for 4 breath cycles. Then start over. Do this for 4 minutes. You can gradually increase the number of minutes with practice. Your mind will wander - especially if you are worried - to worried thoughts. Gently acknowledge this when you become aware that your mind has wandered and return your focus to your breathing. Practice 4x4 every day. With time, this will become something you can turn to to calm yourself.

I am not sure what is going on with your left upper leg except that perhaps you have a strain. Your doctor can check this out. Ibuprofen (taken after eating) may help.

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