Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concern..
As per your complain a lump on left side of neck with difficulty in swallowing and
nasal congestion can be due to viral
throat infection leading to tonsillitis and
Pharyngitis..
Deep cavity in tooth can also lead to swelling of jaw and inflamed lymph nodes but in your case it can be due to throat infection..
I would suggest you to consult an Otolaryngologist and get evaluated and he can do a clinical evaluation and a throat swab culture for ruling out for bacterial or viral infection..
In case of throat infection he can advise you antibiotics like
Levofloxacin, anti-inflammatory painkiller like Ibuprofen, warm saline gargles and steam inhalations can help..
For relieving nasal congestion oral and nasal decongestants can be taken..
In case if it is dental issue you will be referred to a
dentist and an x ray will help in planning out the treatment..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.