A severe Anxiety episode can cause severe chest pain and some people say it feels just like a Heart Attack because the pain is so severe.
What you have described is NOT Pnuemonia and it is definitely not cancer. Your pain is muscular. When someone is having muscular pain, when they press on the area the pain is eminating from it will feel tender, sore or very painful to the touch. This is muscular and nothing to worry about.
It does sound like you need to return to your Doctor about sleeping a lot. This could be depression related or it could be caused by mild Anemia or it simply may be due to you having a lack of energy which has made you very tired.
Please do not worry because it is nothing serious and it will clear up on its own. Go to your local chemist/pharmacist and purchase some rubbing cream/lotion or oil for a pulled muscle or muscular pain and apply this to your chest area and around the side. This will help with the pain or alternatively, take painkillers for the pain.
If it hasn't gone in 2 weeks then see your Doctor for something stronger. Meanwhile take it easy and dont worry so much.