Had a tooth extraction and bone graft 3 weeks ago. Yesterday noted swelling and pain. No redness or oozing from site. Possible food irritation?

Possible. Is there any reason why you would not give a simple call to the author of the extraction....he/she would be best to see you as a postop & be able to answer this question quicklly.
Possible.. But any swelling or pain should be evaluated by your surgeon. Give them a call for an immediate follow up appointment.
Definitely, yes. You should avoid popcorn, nuts and seeds and hard food for 6 weeks after your extractions. If concerned see your dentist for evaluation.
Food trauma. Possibly food trauma. More likely an infection.Have your surgeon evaluate this for medications.

Related Questions

I had a tooth extraction, bone graft surgery 3 days ago. Swelling and pain are horrible, gum is black/grey, dark red lump around it. Is it infected?

Not via computer. You need to be immediately evaluated by Dentist, Periodontist, or Oral Surgeon that did extraction. You may need additional treatment and/or antibiotics. Read more...
Possibly. But without knowing the extent of the surgery or the graft, and without being able to see you, it is impossible to tell. Your best bet is to call the surgeon who performed the procedure and be re-evaluated. Read more...

Can low nutrition affect the healing of tooth extractions and bone graft?

Yes. Adequate nutrition is necessary for all healing of the body. Bone grafts require adequate calcium and vitamin D for healing. Please talk to your doctor or see a nutritionist for advice on improving your diet. Read more...
Sure. There are no true clinical studies on this but health & healthy eating can effect healing properties in the body so why not healing of an extraction site. Most important is clotting factors etc. Read more...
Of course. because balanced diet with vitamin C, vitamins A, E, B, K and D are essential for healing. Read more...