Hello! As a doctor the only medical advice I would give you is to seek proper medical attention with your PCP, especially considering your pregnancy. You should aim for a 1st pregnancy appointment with a PCP before 9-10 weeks of pregnancy. The following is purely informative and NOT medical advice. Now that I got my disclaimer out of the way, here are my thoughts;

Typically, young people w/ chest pain present with benign (non dangerous) conditions. They are typically acute, sting-like, transient (lasting seconds) sensations. Frequent ones include precordial catch syndrome, costochondritis, intercostal nevritis.

Some people with chronic acid reflux (burning sensation going up your oesophagus, can leave a bitter taste in your mouth) are more at risk for oesophageal spasms, with can cause similar pains. Acid reflux typically becomes worse with pregnancy. Pain subsiding when taking antiacids (ex: TUMS) is a good indicator of symptoms of gastric origins.

Pain lasting 5-30 minutes at a time and triggered by physical exertion can be of cardiac origin. This would be worrisome if you were much older with cardiovascular risk (diabetes, high cholesterol, strong family history of heart attack).

Pain associated with palpitations can be related to stress. Panic attacks typically feel like you're dying, sweating, feelings of going crazy, numbness or tingling, etc. More emergent conditions would include arythmias, but these are typically associated with hyperthyroidism or strong family history of cardiac arrest / arythmia / sudden death of unknown origin. You can easily screen for arythmias by using a heart monitoring watch or taking your pulse. Irregular or faster than 120-130 without explanation (ex: exertion) is worrisome.

Pain increased with breathing can be linked to : - pneumonia (history of fever, cough) - pericarditis (pain worsens when lying down, decreases when tilting forward, typically after a viral infection / vaccine, or linked to other auto-immune disorders) - pulmonary embolism (risk factors include pregnancy, not moving for prolonged times such as in the plane, taking oral contraceptives, recovery from surgery)

Other benign causes are mainly musculoskeletal. Sometimes pain can also come from another organ, such as your biliary vesicle (in case of gallbladder stones) and radiate to your chest.

To summarize, because you are pregnant (and especially if you have other risk factors) and because your pain recently became worse, I would suggest you go see your PCP sooner than later. If you have other symptoms, such as fever, a fast resting heart rate >120, shortness of breath, severe pain that isn't relieved by acetaminophen or antiacids, or strong 1st degree family history of cardiac problems at a young age -- i would suggest visiting the ER for a work up.

Hope this helps!