Thanks for your post.
Long term use of NSAIDs like Naproxen
can cause side effects specially gastrointestinal discomfort and ulcers. Moreover, some patients are inadequately relieved of pain and inflammation by NSAIDs.
Appropriate alternatives are Cox-2 inhibitors or NSIADs +misoprostol
. Both alternatives can be use for long term and these have less side effect on GIT.
You can take Arthrotec
wich contains diclofenic +misprostrol. Beside you should also take Vit B12 supplements as you are vegetarian.
hope it helps.