I'm sorry to hear you experienced a twinge in your left arm during exercise. This could be due to muscle strain or a minor injury, but since the left arm pain can sometimes be related to heart issues, it’s important to be cautious.

Here are some steps you can take:

• Stop exercising immediately and rest.
• Monitor your symptoms: If the pain persists, worsens, or is accompanied by chest pain, shortness of breath, sweating, nausea, or dizziness, seek emergency medical care right away.
• Apply a cold compress to the area if there is swelling or tenderness.
• Avoid strenuous activity until you have been evaluated.
• If the pain seems muscular, over-the-counter pain relief and muscle relaxants may help, but only take medications prescribed or recommended by a doctor.

Given the potential seriousness, I strongly recommend consulting a cardiologist or your primary care doctor promptly to rule out any cardiac causes and to get a proper diagnosis and treatment plan.

If you experience severe symptoms or worsening pain, please call emergency services immediately.To narrow down potential causes, we will need some more information.I understand you felt a twinge in your left arm during exercise. Please tell me your age and gender.