Taking 5htp for 2 weeks. For 7 days having trouble swallowing, breathing and dry mouth. Can 5htp cause this?

Likely . Muscle weakness could occur. Talk to prescriber for consideration of lowering dose or use another medication .
Maybe Side effects. Make sure you are taking the appropriate dose. These are not common side effects. If you are taking this for anxiety or depression, there are known interactions with other medications for these conditions. Try stopping this supplement for 2 weeks and see if your symptoms disappear. If you want to continue with 5HTP, check with your MD or pharmacist to be sure it is safe for you.