9. Chest Pain

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Chest pain is often described as an uncomfortable and painful tightening of the chest. For some individuals, it is accompanied with pain in your upper arm and sudden sweating and nausea. At worst, this symptom might be a sign of a heart attack. Another less alarming possibility is acid reflux.
8. Unexplained Weight Loss

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Sometimes weight loss can be attributed to a new exercise routine, but if you experience a sharp and startling drop in body weight without actively trying, something might be up. This symptom could be a sign of a serious illness, such as cancer, or an endocrine disorder such as thyroid disease.