I have nasal congestion due to a cold, how can I get relief?

Nasal or oral. For simple nasal congestion after a cold, you can use: oxymetazoline nasal spray, over the counter oral decongestants, or a saline irrigation solution. If you have high blood pressure or other heart issues, the oral decongestant is not the best choice as it is a potential stimulant to the heart. Then the nasal spray might be the better choice. Personally i always recommend the topical solutions.
Nasal congestion. Warm salt water sniffs or long hot shower sudafed if not hypertensive -afrin nasal spray for 3-4 days.