The likely reason that the fruits are causing you pains is because it's the cleanest thing you can eat. Especially when it's ripe and grown properly. When we go from eating processed foods our whole lives to eating the cleanest things for our bodies.....we don't feel well because we are no longer putting the processed stuff in. And the body finally jumps on the opportunity to begin cleaning house. But the issue arises when the body doesn't have enough clear pathways to eliminate the stored excess, so all the released accumulations begin to circulate through the blood. Then the body goes back into overdrive to protect itself. This is where those pains come from when we are cleansing. If you want more insight or understanding on this process then you could study rehab clinics and why people go through withdrawals.
I would recommend a transition diet if it's currently difficult for you to eat much fruit. Ehret and Morse talk about this a bit. Perhaps eating fruit during the morning and as far into the day as possible, then in the evening eat steamed veggies. And I will admit.....it can be a little unpleasent for a short while. For me I had a few days of not feeling so well then days of feeling great, and this continued for a few weeks. But the days of feeling great kept growing and the days of feeling unpleasent quickly became less and went away. The harder you cleanse your body by eating cleaner and cleaner the quicker and more extreme your body will.."detox". So you can always slow that process back down with some cooked food.....sometimes it's things such as steamed veggies or simple salads that will work. But there are also some that when they reach a place of pain that they just can't stand, they will eat a little bit of processed food to practically halt the body from cleansing itself and it will make the pains stop. A few weeks ago someone on the fb page tore into a bag of chips because her headaches were too much for her. In my case I've even used burritos. LOL
I would also recommend staying away from the nuts, "not that you need anyone to tell you that your body doesn't agree with them". The body is already overburdened from an excess of protein consumption in our society and it's the last thing it needs right now in the majority of situations.
As far as eating fruit....do you know of any that do currently agree with you? Watermelon would be great, so would dark grapes. Morse talks about those two a LOT, and it's because they cleanse very well. And for the most part it's currently pretty easy to find some at that are ripe....well I guess if you live in the northern hemisphere anyway. The watermelon is great on the kidneys and the dark grapes are very good for the lymphatic system. And when eating fruit, make it a point to try and select what is currently ripe and in season.
As far as the salt....yes you are correct. Though I wouldn't intentionally limit your daily water. Drink what you desire.
If you want more specific help from people with WAY more experience than I have, then contact Dr. Morse's office. The last I heard he was very busy helping people with intense sicknesses so you may not talk directly with him. And to be honest I don't know if it will cost money or not. Though you can always email him of your situation and I'll bet, that he will do a video response to you. You can also get on fb and look for Dr. Morse fan club....there are many people on there who are very knowledgeable that have gone through some very tough times who are great when you need some insight and support. And I will admit....my knowledge is limited to my situation and the things I've remembered which I felt were important.