The symptoms described cannot be attributed to acidity/gas alone without proper evaluation. Although the pain was mild and transient and previous cardiac investigations were normal, recurrent chest discomfort associated with left-arm numbness should not be ignored. A normal ECG is reassuring but, depending on the timing of symptoms and clinical risk factors, it may not by itself exclude an acute cardiac problem.
Since you are 35 and physically active, musculoskeletal pain, cervical nerve compression, or gastrointestinal causes are also possible. However, a proper clinical examination is required to differentiate these.
“it is just gas” or “your heart is completely normal” based only on the information provided.
Next Steps
If chest pain recurs and is persistent/severe, or is associated with breathlessness, sweating, dizziness, nausea, or pain/discomfort spreading to the arm, jaw, back or neck, seek urgent emergency medical care rather than waiting for an online consultation.
Health Tips
Please consult a physician/cardiologist for examination and review of your current ECG. Depending on the history, your doctor may decide whether further testing such as cardiac biomarkers, echocardiography or other cardiac evaluation is required.