UPDATE! so It took stewie to the vets on the 8/12/16 he was given pain relive and syringeable food and 2 injections, 3 days after he started to eat a little he seemed to of perked up , he was still making those noises I was talking about but otherwise improving, on the 4th day he completely stopped eating and noises sounded worse so the next day I took him back, the said that it maybe his teeth and yet again they said his lungs and heart sound healthy same as the last visit they couldn't check properly as stewie wouldn't let them stewie stayed at the vets over night so they could put him under mild anaesthetic and check his teeth to make sure the back teeth hadn't worn down and caused spikes, I waited all morning for a phone call, in the end I rung them up asking for an update they said it wasn't his teeth his teeth were good, so they decided to do a xray, and asked to come in to collect him and look at xray so I did , they showed me xray and said he has arthritis a little gas in his belly which they gassed out , and a little fluid on his lungs which maybe an infection and that the pain from the arthritis may have caused him to stop eating as guinea pigs will do this if they are in pain , also they said that he had lack of fibre as where I feed him fresh salad daily I may have been feeding him to much, and he favoured salad over the hay and nuiggets ( I feel is not the case I saw hime always eating hay throught the day and nuggets), I may have feed him to much salad but I felt I hadn't I thoiurght I was doing the best thing for them, so I left with more pain relief and antibiotics (this was yesterday) , I kept feeling like when I brought him back from there he seemed worse , I get up this morning to give him his medications and syringe feed him as he hadn't eaten I picked him up and he was not fighting at all as usually stewie would he would want to check everything out to see what he could chew lol so I after I finished feeding him I out him back in his cage with oreo (other guinea pig), 2 minutes after doing so he was sorta jolting put his head under the hay and died, I am absolutely devastated he seemed so much worse after being at the vets the charged me a lot of money ( I payed £230 in 2 weeks ) and they still weren't exactly sure what was causing him not to eat , I'm so upset I really loved this guinea pig and I feel like I let him down, now I have oreo his cage mate who is 7 months old and now alone and I have no idea what I should do I cant bare seeing him alone , thank you to everyone that replied and offered me advice I wish I was typing better news.